Make scripts/powerline use os.environ['PWD'] for .getcwd() if present
Make scripts/powerline use os.environ['PWD'] for .getcwd() if present

Closes #330

firebitsbr/powerline,seanfisk/powerline,magus424/powerline,darac/powerline,S0lll0s/powerline,junix/powerline,cyrixhero/powerline,firebitsbr/powerline,russellb/powerline,Liangjianghao/powerline,Liangjianghao/powerline,darac/powerline,QuLogic/powerline,DoctorJellyface/powerline,prvnkumar/powerline,kenrachynski/powerline,bartvm/powerline,wfscheper/powerline,areteix/powerline,bartvm/powerline,areteix/powerline,s0undt3ch/powerline,russellb/powerline,xfumihiro/powerline,blindFS/powerline,bezhermoso/powerline,xxxhycl2010/powerline,bezhermoso/powerline,blindFS/powerline,bartvm/powerline,DoctorJellyface/powerline,DoctorJellyface/powerline,lukw00/powerline,cyrixhero/powerline,dragon788/powerline,magus424/powerline,russellb/powerline,s0undt3ch/powerline,Luffin/powerline,EricSB/powerline,junix/powerline,xxxhycl2010/powerline,S0lll0s/powerline,prvnkumar/powerline,s0undt3ch/powerline,blindFS/powerline,firebitsbr/powerline,EricSB/powerline,seanfisk/powerline,QuLogic/powerline,seanfisk/powerline,kenrachynski/powerline,darac/powerline,lukw00/powerline,QuLogic/powerline,areteix/powerline,xfumihiro/powerline,prvnkumar/powerline,Luffin/powerline,junix/powerline,IvanAli/powerline,xxxhycl2010/powerline,keelerm84/powerline,magus424/powerline,IvanAli/powerline,bezhermoso/powerline,keelerm84/powerline,dragon788/powerline,xfumihiro/powerline,EricSB/powerline,Liangjianghao/powerline,wfscheper/powerline,S0lll0s/powerline,kenrachynski/powerline,cyrixhero/powerline,lukw00/powerline,Luffin/powerline,dragon788/powerline,IvanAli/powerline,wfscheper/powerline