Two fixes to IPython support:
Two fixes to IPython support:

- Don't attempt to run worker processes with ipython (that can cause
  some crashes as ipython prints things to standard out)
- Allow passing some IPYTHON_OPTS to launch things like the notebook

panfengfeng/spark,xflin/spark,zzcclp/spark,pronix/spark,milliman/spark,andrewor14/spark,zhouyejoe/spark,facaiy/spark,map222/spark,witgo/spark,aokolnychyi/spark,hvanhovell/spark,ddna1021/spark,guoxiaolongzte/spark,nlalevee/spark,sryza/spark,pgandhi999/spark,jianran/spark,loneknightpy/spark,sachintyagi22/spark,shuangshuangwang/spark,shaneknapp/spark,stanzhai/spark,kissmetrics/spark,narahari92/spark,tengpeng/spark,esi-mineset/spark,Aegeaner/spark,ahnqirage/spark,narahari92/spark,pgandhi999/spark,ddna1021/spark,poffuomo/spark,kiszk/spark,gengliangwang/spark,ioana-delaney/spark,rikima/spark,goldmedal/spark,metamx/spark,sureshthalamati/spark,guoxiaolongzte/spark,JerryLead/spark,jlopezmalla/spark,zuotingbing/spark,aosagie/spark,actuaryzhang/spark,bOOm-X/spark,1haodian/spark,ptkool/spark,pronix/spark,xflin/spark,poffuomo/spark,JerryLead/spark,huang1900/spark,publicRoman/spark,someorz/spark,bravo-zhang/spark,sureshthalamati/spark,jkbradley/spark,zero323/spark,cloudera/spark,skonto/spark,janewangfb/spark,wzhfy/spark,yanboliang/spark,janewangfb/spark,michalsenkyr/spark,SnappyDataInc/spark,debugger87/spark,ron8hu/spark,dongjoon-hyun/spark,byakuinss/spark,debugger87/spark,wangmiao1981/spark,pronix/spark,WindCanDie/spark,apache/spark,sahilTakiar/spark,cloud-fan/spark,skonto/spark,dbtsai/spark,cin/spark,holdenk/spark,adrian-ionescu/apache-spark,SHASHANKB/spark,icexelloss/spark,shuangshuangwang/spark,chuckchen/spark,wangmiao1981/spark,HyukjinKwon/spark,cloud-fan/spark,ajaysaini725/spark,zzcclp/spark,liyichao/spark,LantaoJin/spark,dbtsai/spark,panfengfeng/spark,actuaryzhang/spark,icexelloss/spark,minixalpha/spark,patrick-nicholson/spark,byakuinss/spark,SHASHANKB/spark,saturday-shi/spark,jrshust/spark,ueshin/apache-spark,HyukjinKwon/spark,janewangfb/spark,eyalfa/spark,zuotingbing/spark,JerryLead/spark,mdespriee/spark,gengliangwang/spark,ptkool/spark,minixalpha/spark,WeichenXu123/spark,sachintyagi22/spark,vax11780/spark,cin/spark,kimoonkim/spark,wzhfy/spark,byakuinss/spark,maropu/spark,spark-test/spark,highfei2011/spark,narahari92/spark,holdenk/spark,lvdongr/spark,mzl9039/spark,wangmiao1981/spark,lvdongr/spark,cloud-fan/spark,SHASHANKB/spark,apache/spark,apache-spark-on-k8s/spark,loneknightpy/spark,ericvandenbergfb/spark,liutang123/spark,ibm-research-ireland/sparkoscope,byakuinss/spark,aokolnychyi/spark,bdrillard/spark,haowu80s/spark,saltstar/spark,rjpower/spark,WindCanDie/spark,darionyaphet/spark,lxsmnv/spark,ueshin/apache-spark,dotunolafunmiloye/spark,ibm-research-ireland/sparkoscope,actuaryzhang/spark,rikima/spark,dhruve/spark,nilsgrabbert/spark,szhem/spark,jlopezmalla/spark,liutang123/spark,darionyaphet/spark,cloudera/spark,saturday-shi/spark,cin/spark,big-pegasus/spark,srowen/spark,nilsgrabbert/spark,dongjoon-hyun/spark,esi-mineset/spark,cloud-fan/spark,wzhfy/spark,JoshRosen/spark,goldmedal/spark,aokolnychyi/spark,techaddict/spark,Aegeaner/spark,chuckchen/spark,LantaoJin/spark,milliman/spark,ron8hu/spark,kissmetrics/spark,ueshin/apache-spark,alunarbeach/spark,nlalevee/spark,alunarbeach/spark,maropu/spark,wzhfy/spark,tejasapatil/spark,ptkool/spark,hhbyyh/spark,mzl9039/spark,andrewor14/iolap,panfengfeng/spark,ron8hu/spark,kevinyu98/spark,rednaxelafx/apache-spark,byakuinss/spark,JoshRosen/spark,facaiy/spark,holdenk/spark,janewangfb/spark,rednaxelafx/apache-spark,apache/spark,metamx/spark,cin/spark,alunarbeach/spark,jlopezmalla/spark,stanzhai/spark,panfengfeng/spark,nchammas/spark,kissmetrics/spark,JerryLead/spark,dongjoon-hyun/spark,tejasapatil/spark,sureshthalamati/spark,markhamstra/spark,akopich/spark,brad-kaiser/spark,WindCanDie/spark,eyalfa/spark,WeichenXu123/spark,skonto/spark,wangmiao1981/spark,spark-test/spark,WindCanDie/spark,Aegeaner/spark,ddna1021/spark,aokolnychyi/spark,jrshust/spark,liyichao/spark,srowen/spark,srowen/spark,shuangshuangwang/spark,cin/spark,mzl9039/spark,rjpower/spark,joseph-torres/spark,esi-mineset/spark,sachintyagi22/spark,andrewor14/spark,WindCanDie/spark,bdrillard/spark,shaneknapp/spark,ddna1021/spark,mzl9039/spark,stanzhai/spark,techaddict/spark,pgandhi999/spark,dbtsai/spark,ConeyLiu/spark,vax11780/spark,vax11780/spark,liyichao/spark,ahnqirage/spark,map222/spark,skonto/spark,hhbyyh/spark,ConeyLiu/spark,WeichenXu123/spark,andrewor14/iolap,patrick-nicholson/spark,dhruve/spark,big-pegasus/spark,wangyum/spark,goldmedal/spark,shaneknapp/spark,milliman/spark,rezasafi/spark,WindCanDie/spark,someorz/spark,shubhamchopra/spark,haowu80s/spark,maropu/spark,jlopezmalla/spark,bOOm-X/spark,icexelloss/spark,HyukjinKwon/spark,markhamstra/spark,HyukjinKwon/spark,michalsenkyr/spark,jiangxb1987/spark,ioana-delaney/spark,michalsenkyr/spark,shuangshuangwang/spark,markhamstra/spark,liutang123/spark,big-pegasus/spark,caneGuy/spark,gioenn/xSpark,aosagie/spark,jlopezmalla/spark,shaneknapp/spark,eyalfa/spark,zzcclp/spark,highfei2011/spark,nchammas/spark,rednaxelafx/apache-spark,pgandhi999/spark,nchammas/spark,actuaryzhang/spark,cloudera/spark,1haodian/spark,WeichenXu123/spark,wangyum/spark,darionyaphet/spark,jiangxb1987/spark,yanboliang/spark,xflin/spark,ConeyLiu/spark,actuaryzhang/spark,esi-mineset/spark,dongjoon-hyun/spark,kevinyu98/spark,setjet/spark,JerryLead/spark,darionyaphet/spark,panfengfeng/spark,kiszk/spark,ptkool/spark,alunarbeach/spark,wangyum/spark,lvdongr/spark,vax11780/spark,hvanhovell/spark,hhbyyh/spark,dotunolafunmiloye/spark,actuaryzhang/spark,highfei2011/spark,LantaoJin/spark,LantaoJin/spark,Panos-Bletsos/spark-cost-model-optimizer,BryanCutler/spark,joseph-torres/spark,someorz/spark,chuckchen/spark,panfengfeng/spark,dhruve/spark,dhruve/spark,BryanCutler/spark,rekhajoshm/spark,pgandhi999/spark,lvdongr/spark,markhamstra/spark,poffuomo/spark,liyichao/spark,vinodkc/spark,apache/spark,apache/spark,byakuinss/spark,minixalpha/spark,saturday-shi/spark,szhem/spark,mike0sv/spark,maropu/spark,andrewor14/iolap,big-pegasus/spark,publicRoman/spark,rjpower/spark,loneknightpy/spark,mahak/spark,WindCanDie/spark,ptkool/spark,Aegeaner/spark,gengliangwang/spark,gioenn/xSpark,kevinyu98/spark,facaiy/spark,kimoonkim/spark,BryanCutler/spark,Panos-Bletsos/spark-cost-model-optimizer,patrick-nicholson/spark,kiszk/spark,kevinyu98/spark,shuangshuangwang/spark,haowu80s/spark,ptkool/spark,sryza/spark,UndeadBaneGitHub/spark,janewangfb/spark,dbtsai/spark,nlalevee/spark,xflin/spark,kiszk/spark,caneGuy/spark,goldmedal/spark,huang1900/spark,zuotingbing/spark,Aegeaner/spark,pgandhi999/spark,apache-spark-on-k8s/spark,mahak/spark,ibm-research-ireland/sparkoscope,haowu80s/spark,saturday-shi/spark,kevinyu98/spark,MLnick/spark,chuckchen/spark,saturday-shi/spark,nchammas/spark,kimoonkim/spark,mzl9039/spark,zero323/spark,poffuomo/spark,caneGuy/spark,taroplus/spark,saltstar/spark,yanboliang/spark,SnappyDataInc/spark,joseph-torres/spark,metamx/spark,SHASHANKB/spark,kevinyu98/spark,ahnqirage/spark,milliman/spark,apache/spark,rednaxelafx/apache-spark,kimoonkim/spark,dhruve/spark,spark-test/spark,mike0sv/spark,holdenk/spark,metamx/spark,tengpeng/spark,holdenk/spark,xuanyuanking/spark,wzhfy/spark,poffuomo/spark,saltstar/spark,BryanCutler/spark,narahari92/spark,sahilTakiar/spark,akopich/spark,zero323/spark,lxsmnv/spark,jiangxb1987/spark,someorz/spark,bravo-zhang/spark,brad-kaiser/spark,apache-spark-on-k8s/spark,caneGuy/spark,ron8hu/spark,sryza/spark,JoshRosen/spark,eyalfa/spark,vax11780/spark,hhbyyh/spark,huang1900/spark,xuanyuanking/spark,jianran/spark,akopich/spark,1haodian/spark,haowu80s/spark,patrick-nicholson/spark,ericvandenbergfb/spark,markhamstra/spark,Panos-Bletsos/spark-cost-model-optimizer,debugger87/spark,markhamstra/spark,ioana-delaney/spark,aray/spark,highfei2011/spark,taroplus/spark,UndeadBaneGitHub/spark,MLnick/spark,kimoonkim/spark,esi-mineset/spark,cloudera/spark,HyukjinKwon/spark,yanboliang/spark,debugger87/spark,liyichao/spark,alunarbeach/spark,matthewfranglen/spark,bravo-zhang/spark,mkolod/incubator-spark,zzcclp/spark,bravo-zhang/spark,minixalpha/spark,andrewor14/iolap,dotunolafunmiloye/spark,hvanhovell/spark,aosagie/spark,1haodian/spark,hvanhovell/spark,adrian-ionescu/apache-spark,sureshthalamati/spark,ioana-delaney/spark,zero323/spark,BryanCutler/spark,zhouyejoe/spark,yanboliang/spark,ConeyLiu/spark,narahari92/spark,jkbradley/spark,tejasapatil/spark,nilsgrabbert/spark,xflin/spark,Panos-Bletsos/spark-cost-model-optimizer,jkbradley/spark,nlalevee/spark,JerryLead/spark,metamx/spark,hvanhovell/spark,ConeyLiu/spark,MLnick/spark,kevinyu98/spark,liutang123/spark,tengpeng/spark,big-pegasus/spark,sachintyagi22/spark,tengpeng/spark,zzcclp/spark,shuangshuangwang/spark,techaddict/spark,sachintyagi22/spark,zero323/spark,szhem/spark,big-pegasus/spark,rekhajoshm/spark,publicRoman/spark,liyichao/spark,dongjoon-hyun/spark,michalsenkyr/spark,ddna1021/spark,brad-kaiser/spark,guoxiaolongzte/spark,ericvandenbergfb/spark,ueshin/apache-spark,lvdongr/spark,hvanhovell/spark,adrian-ionescu/apache-spark,milliman/spark,andrewor14/spark,vinodkc/spark,UndeadBaneGitHub/spark,witgo/spark,jianran/spark,UndeadBaneGitHub/spark,facaiy/spark,patrick-nicholson/spark,setjet/spark,jkbradley/spark,bOOm-X/spark,milliman/spark,shaneknapp/spark,HyukjinKwon/spark,tejasapatil/spark,lxsmnv/spark,shuangshuangwang/spark,bravo-zhang/spark,xflin/spark,aray/spark,shubhamchopra/spark,sureshthalamati/spark,metamx/spark,jkbradley/spark,rekhajoshm/spark,1haodian/spark,SnappyDataInc/spark,highfei2011/spark,gengliangwang/spark,xuanyuanking/spark,publicRoman/spark,dbtsai/spark,setjet/spark,ron8hu/spark,pronix/spark,cloudera/spark,ddna1021/spark,michalsenkyr/spark,ahnqirage/spark,patrick-nicholson/spark,xuanyuanking/spark,sahilTakiar/spark,taroplus/spark,akopich/spark,joseph-torres/spark,aray/spark,dhruve/spark,eyalfa/spark,wangmiao1981/spark,srowen/spark,map222/spark,ibm-research-ireland/sparkoscope,rikima/spark,huang1900/spark,setjet/spark,saltstar/spark,szhem/spark,saturday-shi/spark,michalsenkyr/spark,maropu/spark,tengpeng/spark,ConeyLiu/spark,darionyaphet/spark,gioenn/xSpark,markhamstra/spark,andrewor14/spark,vinodkc/spark,ericvandenbergfb/spark,debugger87/spark,holdenk/spark,kissmetrics/spark,caneGuy/spark,dotunolafunmiloye/spark,JerryLead/spark,gioenn/xSpark,MLnick/spark,jiangxb1987/spark,MLnick/spark,setjet/spark,HyukjinKwon/spark,gioenn/xSpark,SHASHANKB/spark,mike0sv/spark,jianran/spark,wangyum/spark,bravo-zhang/spark,brad-kaiser/spark,sahilTakiar/spark,kimoonkim/spark,chuckchen/spark,nilsgrabbert/spark,loneknightpy/spark,huang1900/spark,LantaoJin/spark,kissmetrics/spark,chuckchen/spark,apache/spark,aokolnychyi/spark,saltstar/spark,darionyaphet/spark,sachintyagi22/spark,SHASHANKB/spark,JoshRosen/spark,someorz/spark,huang1900/spark,dongjoon-hyun/spark,BryanCutler/spark,ajaysaini725/spark,zhouyejoe/spark,sryza/spark,akopich/spark,aray/spark,haowu80s/spark,alunarbeach/spark,jiangxb1987/spark,map222/spark,setjet/spark,wangyum/spark,liutang123/spark,mike0sv/spark,kimoonkim/spark,highfei2011/spark,ahnqirage/spark,ueshin/apache-spark,bdrillard/spark,eyalfa/spark,apache-spark-on-k8s/spark,liyichao/spark,ueshin/apache-spark,metamx/spark,caneGuy/spark,jrshust/spark,nlalevee/spark,zero323/spark,joseph-torres/spark,lxsmnv/spark,adrian-ionescu/apache-spark,ibm-research-ireland/sparkoscope,icexelloss/spark,mahak/spark,jrshust/spark,facaiy/spark,sryza/spark,patrick-nicholson/spark,rekhajoshm/spark,ericvandenbergfb/spark,taroplus/spark,techaddict/spark,mkolod/incubator-spark,liutang123/spark,WeichenXu123/spark,shubhamchopra/spark,mkolod/incubator-spark,SnappyDataInc/spark,aosagie/spark,shubhamchopra/spark,vinodkc/spark,skonto/spark,publicRoman/spark,shubhamchopra/spark,panfengfeng/spark,aosagie/spark,huang1900/spark,kiszk/spark,shaneknapp/spark,kissmetrics/spark,bravo-zhang/spark,Panos-Bletsos/spark-cost-model-optimizer,akopich/spark,bdrillard/spark,saturday-shi/spark,yanboliang/spark,zhouyejoe/spark,rekhajoshm/spark,jkbradley/spark,stanzhai/spark,poffuomo/spark,darionyaphet/spark,zero323/spark,mdespriee/spark,jrshust/spark,WeichenXu123/spark,rednaxelafx/apache-spark,jrshust/spark,nchammas/spark,aokolnychyi/spark,ajaysaini725/spark,icexelloss/spark,SHASHANKB/spark,tejasapatil/spark,janewangfb/spark,cloud-fan/spark,eyalfa/spark,Aegeaner/spark,publicRoman/spark,hhbyyh/spark,tengpeng/spark,poffuomo/spark,rezasafi/spark,ueshin/apache-spark,highfei2011/spark,map222/spark,mike0sv/spark,sureshthalamati/spark,nilsgrabbert/spark,xuanyuanking/spark,SnappyDataInc/spark,gioenn/xSpark,rezasafi/spark,cin/spark,mike0sv/spark,sahilTakiar/spark,jiangxb1987/spark,minixalpha/spark,zuotingbing/spark,michalsenkyr/spark,rekhajoshm/spark,sahilTakiar/spark,facaiy/spark,stanzhai/spark,stanzhai/spark,maropu/spark,srowen/spark,jianran/spark,mdespriee/spark,shubhamchopra/spark,map222/spark,aokolnychyi/spark,akopich/spark,apache-spark-on-k8s/spark,apache-spark-on-k8s/spark,goldmedal/spark,rikima/spark,ajaysaini725/spark,janewangfb/spark,1haodian/spark,cloud-fan/spark,spark-test/spark,sureshthalamati/spark,mahak/spark,chuckchen/spark,bdrillard/spark,minixalpha/spark,bOOm-X/spark,bOOm-X/spark,tejasapatil/spark,kiszk/spark,LantaoJin/spark,rezasafi/spark,facaiy/spark,taroplus/spark,witgo/spark,nchammas/spark,ioana-delaney/spark,someorz/spark,UndeadBaneGitHub/spark,techaddict/spark,mzl9039/spark,guoxiaolongzte/spark,srowen/spark,ioana-delaney/spark,zhouyejoe/spark,jrshust/spark,JoshRosen/spark,lxsmnv/spark,cloud-fan/spark,hvanhovell/spark,stanzhai/spark,pronix/spark,debugger87/spark,aray/spark,hhbyyh/spark,wzhfy/spark,aray/spark,zuotingbing/spark,hhbyyh/spark,UndeadBaneGitHub/spark,shubhamchopra/spark,saltstar/spark,esi-mineset/spark,goldmedal/spark,Panos-Bletsos/spark-cost-model-optimizer,bdrillard/spark,andrewor14/spark,zuotingbing/spark,skonto/spark,dhruve/spark,SnappyDataInc/spark,shaneknapp/spark,lxsmnv/spark,caneGuy/spark,ajaysaini725/spark,mdespriee/spark,aray/spark,pronix/spark,brad-kaiser/spark,lvdongr/spark,bOOm-X/spark,witgo/spark,rednaxelafx/apache-spark,sachintyagi22/spark,mahak/spark,jkbradley/spark,ddna1021/spark,MLnick/spark,rezasafi/spark,xflin/spark,Panos-Bletsos/spark-cost-model-optimizer,brad-kaiser/spark,xuanyuanking/spark,techaddict/spark,WeichenXu123/spark,taroplus/spark,bOOm-X/spark,loneknightpy/spark,adrian-ionescu/apache-spark,ajaysaini725/spark,ibm-research-ireland/sparkoscope,rikima/spark,spark-test/spark,andrewor14/spark,icexelloss/spark,liutang123/spark,rikima/spark,skonto/spark,JoshRosen/spark,mkolod/incubator-spark,alunarbeach/spark,cin/spark,map222/spark,taroplus/spark,techaddict/spark,zhouyejoe/spark,vinodkc/spark,xuanyuanking/spark,witgo/spark,big-pegasus/spark,rjpower/spark,zzcclp/spark,milliman/spark,maropu/spark,pgandhi999/spark,guoxiaolongzte/spark,tejasapatil/spark,guoxiaolongzte/spark,gengliangwang/spark,ahnqirage/spark,saltstar/spark,mike0sv/spark,mahak/spark,MLnick/spark,ajaysaini725/spark,lxsmnv/spark,mdespriee/spark,actuaryzhang/spark,andrewor14/spark,loneknightpy/spark,esi-mineset/spark,ibm-research-ireland/sparkoscope,loneknightpy/spark,mdespriee/spark,nilsgrabbert/spark,icexelloss/spark,zzcclp/spark,someorz/spark,witgo/spark,joseph-torres/spark,minixalpha/spark,jianran/spark,debugger87/spark,ahnqirage/spark,dbtsai/spark,holdenk/spark,gengliangwang/spark,andrewor14/iolap,jlopezmalla/spark,mkolod/incubator-spark,dbtsai/spark,Aegeaner/spark,vinodkc/spark,jlopezmalla/spark,UndeadBaneGitHub/spark,andrewor14/iolap,ericvandenbergfb/spark,adrian-ionescu/apache-spark,dongjoon-hyun/spark,goldmedal/spark,wzhfy/spark,guoxiaolongzte/spark,setjet/spark,apache-spark-on-k8s/spark,ptkool/spark,spark-test/spark,joseph-torres/spark,wangmiao1981/spark,gengliangwang/spark,andrewor14/iolap,szhem/spark,ron8hu/spark,narahari92/spark,rezasafi/spark,wangyum/spark,vinodkc/spark,rednaxelafx/apache-spark,kiszk/spark,publicRoman/spark,nlalevee/spark,spark-test/spark,wangmiao1981/spark,ConeyLiu/spark,witgo/spark,SnappyDataInc/spark,byakuinss/spark,nchammas/spark,mahak/spark,szhem/spark,kissmetrics/spark,lvdongr/spark,mzl9039/spark,adrian-ionescu/apache-spark,gioenn/xSpark,jianran/spark,wangyum/spark,tengpeng/spark,ericvandenbergfb/spark,LantaoJin/spark,ioana-delaney/spark,BryanCutler/spark,srowen/spark,ron8hu/spark,bdrillard/spark,jiangxb1987/spark,nilsgrabbert/spark,JoshRosen/spark,mdespriee/spark,zhouyejoe/spark,rezasafi/spark,aosagie/spark,sahilTakiar/spark,aosagie/spark,nlalevee/spark,szhem/spark,yanboliang/spark,1haodian/spark,zuotingbing/spark,rikima/spark,rjpower/spark,narahari92/spark,rekhajoshm/spark,brad-kaiser/spark