modify MXDataIter to to provide data/label info
modify MXDataIter to to provide data/label info

EvanzzzZ/mxnet,Northrend/mxnet,arank/mxnet,precedenceguo/mxnet,ZihengJiang/mxnet,hesseltuinhof/mxnet,yajiedesign/mxnet,ptrendx/mxnet,arank/mxnet,arikpoz/mxnet,pluskid/mxnet,madjam/mxnet,crazy-cat/incubator-mxnet,thirdwing/mxnet,zhreshold/mxnet,CodingCat/mxnet,szha/mxnet,thirdwing/mxnet,DR08/mxnet,smolix/incubator-mxnet,leezu/mxnet,tlby/mxnet,ptrendx/mxnet,szha/mxnet,dmlc/mxnet,precedenceguo/mxnet,jiajiechen/mxnet,piiswrong/mxnet,rishita/mxnet,ShownX/incubator-mxnet,rahul003/mxnet,TuSimple/mxnet,jiajiechen/mxnet,luoyetx/mxnet,DickJC123/mxnet,kevinthesun/mxnet,jennyzhang0215/incubator-mxnet,stefanhenneking/mxnet,navrasio/mxnet,kkk669/mxnet,wangyum/mxnet,hotpxl/mxnet,jiajiechen/mxnet,formath/mxnet,jamesliu/mxnet,Guneet-Dhillon/mxnet,mbaijal/incubator-mxnet,hotpxl/mxnet,wangyum/mxnet,TuSimple/mxnet,ykim362/mxnet,larroy/mxnet,Guneet-Dhillon/mxnet,saurabh3949/mxnet,apache/incubator-mxnet,yajiedesign/mxnet,danithaca/mxnet,formath/mxnet,hesseltuinhof/mxnet,Ldpe2G/mxnet,arank/mxnet,dmlc/mxnet,Prasad9/incubator-mxnet,solin319/incubator-mxnet,jamesliu/mxnet,thirdwing/mxnet,ZihengJiang/mxnet,leezu/mxnet,CodingCat/mxnet,EvanzzzZ/mxnet,likelyzhao/mxnet,precedenceguo/mxnet,ptrendx/mxnet,tornadomeet/mxnet,vikingMei/mxnet,xcgoner/dist-mxnet,Prasad9/incubator-mxnet,piiswrong/mxnet,crazy-cat/incubator-mxnet,weleen/mxnet,ptrendx/mxnet,ykim362/mxnet,TuSimple/mxnet,gautamkmr/incubator-mxnet,jennyzhang0215/incubator-mxnet,EvanzzzZ/mxnet,madjam/mxnet,arank/mxnet,pluskid/mxnet,solin319/incubator-mxnet,kevinthesun/mxnet,saurabh3949/mxnet,LinkHS/incubator-mxnet,antoan2/incubator-mxnet,kkk669/mxnet,pluskid/mxnet,zhreshold/mxnet,solin319/incubator-mxnet,saurabh3949/mxnet,Northrend/mxnet,smolix/incubator-mxnet,TuSimple/mxnet,jamesliu/mxnet,LinkHS/incubator-mxnet,larroy/mxnet,hotpxl/mxnet,reminisce/mxnet,kkk669/mxnet,Mega-DatA-Lab/mxnet,arikpoz/mxnet,jennyzhang0215/incubator-mxnet,nicklhy/mxnet,crazy-cat/incubator-mxnet,ForkedReposBak/mxnet,apaleyes/mxnet,LinkHS/incubator-mxnet,apaleyes/mxnet,luoyetx/mxnet,yajiedesign/mxnet,jiajiechen/mxnet,hotpxl/mxnet,gautamkmr/incubator-mxnet,TuSimple/mxnet,vikingMei/mxnet,lxn2/mxnet,weleen/mxnet,weleen/mxnet,eric-haibin-lin/mxnet,vikingMei/mxnet,indhub/mxnet,yuruofeifei/mxnet,nicklhy/mxnet,saurabh3949/mxnet,tornadomeet/mxnet,rahul003/mxnet,Guneet-Dhillon/mxnet,danithaca/mxnet,madjam/mxnet,sxjscience/mxnet,tornadomeet/mxnet,rahul003/mxnet,rishita/mxnet,tornadomeet/mxnet,yuruofeifei/mxnet,DR08/mxnet,Mega-DatA-Lab/mxnet,apaleyes/mxnet,wangyum/mxnet,apache/incubator-mxnet,precedenceguo/mxnet,danithaca/mxnet,DR08/mxnet,Northrend/mxnet,sergeykolychev/mxnet,DickJC123/mxnet,ZihengJiang/mxnet,CodingCat/mxnet,indhub/mxnet,tlby/mxnet,jennyzhang0215/incubator-mxnet,madjam/mxnet,eric-haibin-lin/mxnet,formath/mxnet,ForkedReposBak/mxnet,lxn2/mxnet,arikpoz/mxnet,likelyzhao/mxnet,ZihengJiang/mxnet,gautamkmr/incubator-mxnet,likelyzhao/mxnet,formath/mxnet,LinkHS/incubator-mxnet,arikpoz/mxnet,mbaijal/incubator-mxnet,thirdwing/mxnet,leezu/mxnet,gautamkmr/incubator-mxnet,stefanhenneking/mxnet,yuruofeifei/mxnet,ptrendx/mxnet,ptrendx/mxnet,rishita/mxnet,LinkHS/incubator-mxnet,Ldpe2G/mxnet,weleen/mxnet,weleen/mxnet,precedenceguo/mxnet,tornadomeet/mxnet,kevinthesun/mxnet,yajiedesign/mxnet,apaleyes/mxnet,tlby/mxnet,hotpxl/mxnet,Ldpe2G/mxnet,saurabh3949/mxnet,CodingCat/mxnet,hpi-xnor/BMXNet,jennyzhang0215/incubator-mxnet,nicklhy/mxnet,nicklhy/mxnet,pluskid/mxnet,ZihengJiang/mxnet,larroy/mxnet,navrasio/mxnet,fullfanta/mxnet,hpi-xnor/BMXNet,antoan2/incubator-mxnet,CodingCat/mxnet,LinkHS/incubator-mxnet,EvanzzzZ/mxnet,hpi-xnor/BMXNet,piiswrong/mxnet,sergeykolychev/mxnet,danithaca/mxnet,arikpoz/mxnet,ykim362/mxnet,piiswrong/mxnet,rishita/mxnet,xcgoner/dist-mxnet,zhreshold/mxnet,formath/mxnet,Guneet-Dhillon/mxnet,Mega-DatA-Lab/mxnet,jamesliu/mxnet,antoan2/incubator-mxnet,vikingMei/mxnet,ForkedReposBak/mxnet,jermainewang/mxnet,yuruofeifei/mxnet,arank/mxnet,luoyetx/mxnet,kevinthesun/mxnet,mbaijal/incubator-mxnet,ForkedReposBak/mxnet,vikingMei/mxnet,EvanzzzZ/mxnet,saurabh3949/mxnet,TuSimple/mxnet,coder-james/mxnet,arank/mxnet,dmlc/mxnet,precedenceguo/mxnet,indhub/mxnet,hpi-xnor/BMXNet,madjam/mxnet,crazy-cat/incubator-mxnet,stefanhenneking/mxnet,DR08/mxnet,jennyzhang0215/incubator-mxnet,crazy-cat/incubator-mxnet,thirdwing/mxnet,weleen/mxnet,pluskid/mxnet,smolix/incubator-mxnet,fullfanta/mxnet,tlby/mxnet,antoan2/incubator-mxnet,Mega-DatA-Lab/mxnet,vikingMei/mxnet,arikpoz/mxnet,reminisce/mxnet,danithaca/mxnet,Ldpe2G/mxnet,szha/mxnet,sxjscience/mxnet,jennyzhang0215/incubator-mxnet,fullfanta/mxnet,jamesliu/mxnet,wangyum/mxnet,EvanzzzZ/mxnet,piiswrong/mxnet,formath/mxnet,reminisce/mxnet,DR08/mxnet,sxjscience/mxnet,jamesliu/mxnet,hesseltuinhof/mxnet,jermainewang/mxnet,reminisce/mxnet,dmlc/mxnet,jermainewang/mxnet,precedenceguo/mxnet,LinkHS/incubator-mxnet,hotpxl/mxnet,luoyetx/mxnet,TuSimple/mxnet,hesseltuinhof/mxnet,apaleyes/mxnet,smolix/incubator-mxnet,likelyzhao/mxnet,sxjscience/mxnet,sxjscience/mxnet,jamesliu/mxnet,sergeykolychev/mxnet,wangyum/mxnet,ptrendx/mxnet,coder-james/mxnet,hpi-xnor/BMXNet,crazy-cat/incubator-mxnet,ForkedReposBak/mxnet,fullfanta/mxnet,lxn2/mxnet,fullfanta/mxnet,navrasio/mxnet,leezu/mxnet,ykim362/mxnet,ZihengJiang/mxnet,CodingCat/mxnet,smolix/incubator-mxnet,piiswrong/mxnet,hesseltuinhof/mxnet,Northrend/mxnet,apaleyes/mxnet,jermainewang/mxnet,apache/incubator-mxnet,stefanhenneking/mxnet,yuruofeifei/mxnet,CodingCat/mxnet,tornadomeet/mxnet,wangyum/mxnet,fullfanta/mxnet,xcgoner/dist-mxnet,smolix/incubator-mxnet,navrasio/mxnet,Mega-DatA-Lab/mxnet,Prasad9/incubator-mxnet,lxn2/mxnet,likelyzhao/mxnet,hesseltuinhof/mxnet,Mega-DatA-Lab/mxnet,lxn2/mxnet,luoyetx/mxnet,jermainewang/mxnet,jamesliu/mxnet,eric-haibin-lin/mxnet,zhreshold/mxnet,crazy-cat/incubator-mxnet,coder-james/mxnet,coder-james/mxnet,luoyetx/mxnet,Ldpe2G/mxnet,xcgoner/dist-mxnet,madjam/mxnet,arikpoz/mxnet,apaleyes/mxnet,smolix/incubator-mxnet,nicklhy/mxnet,rishita/mxnet,jiajiechen/mxnet,hpi-xnor/BMXNet,arank/mxnet,thirdwing/mxnet,ptrendx/mxnet,DR08/mxnet,sergeykolychev/mxnet,CodingCat/mxnet,Mega-DatA-Lab/mxnet,larroy/mxnet,arank/mxnet,dmlc/mxnet,hpi-xnor/BMXNet,kevinthesun/mxnet,apache/incubator-mxnet,eric-haibin-lin/mxnet,rishita/mxnet,navrasio/mxnet,madjam/mxnet,hotpxl/mxnet,Prasad9/incubator-mxnet,ptrendx/mxnet,saurabh3949/mxnet,jennyzhang0215/incubator-mxnet,sxjscience/mxnet,zhreshold/mxnet,antoan2/incubator-mxnet,larroy/mxnet,Prasad9/incubator-mxnet,hotpxl/mxnet,tlby/mxnet,ShownX/incubator-mxnet,indhub/mxnet,formath/mxnet,wangyum/mxnet,navrasio/mxnet,eric-haibin-lin/mxnet,tlby/mxnet,precedenceguo/mxnet,indhub/mxnet,hpi-xnor/BMXNet,lxn2/mxnet,ykim362/mxnet,dmlc/mxnet,rahul003/mxnet,zhreshold/mxnet,formath/mxnet,rahul003/mxnet,hesseltuinhof/mxnet,tornadomeet/mxnet,Guneet-Dhillon/mxnet,ShownX/incubator-mxnet,reminisce/mxnet,zhreshold/mxnet,kkk669/mxnet,jermainewang/mxnet,kevinthesun/mxnet,antoan2/incubator-mxnet,jennyzhang0215/incubator-mxnet,tornadomeet/mxnet,stefanhenneking/mxnet,solin319/incubator-mxnet,TuSimple/mxnet,mbaijal/incubator-mxnet,Northrend/mxnet,apaleyes/mxnet,xcgoner/dist-mxnet,dmlc/mxnet,arikpoz/mxnet,EvanzzzZ/mxnet,mbaijal/incubator-mxnet,antoan2/incubator-mxnet,szha/mxnet,jermainewang/mxnet,ZihengJiang/mxnet,solin319/incubator-mxnet,smolix/incubator-mxnet,navrasio/mxnet,lxn2/mxnet,Northrend/mxnet,DR08/mxnet,hpi-xnor/BMXNet,leezu/mxnet,ShownX/incubator-mxnet,Guneet-Dhillon/mxnet,zhreshold/mxnet,coder-james/mxnet,antoan2/incubator-mxnet,solin319/incubator-mxnet,Mega-DatA-Lab/mxnet,sergeykolychev/mxnet,ShownX/incubator-mxnet,ForkedReposBak/mxnet,reminisce/mxnet,luoyetx/mxnet,likelyzhao/mxnet,indhub/mxnet,szha/mxnet,yuruofeifei/mxnet,ykim362/mxnet,nicklhy/mxnet,sergeykolychev/mxnet,fullfanta/mxnet,yajiedesign/mxnet,rahul003/mxnet,yuruofeifei/mxnet,hesseltuinhof/mxnet,kkk669/mxnet,Ldpe2G/mxnet,ForkedReposBak/mxnet,ZihengJiang/mxnet,Guneet-Dhillon/mxnet,vikingMei/mxnet,kkk669/mxnet,yuruofeifei/mxnet,saurabh3949/mxnet,navrasio/mxnet,arank/mxnet,mbaijal/incubator-mxnet,jiajiechen/mxnet,kkk669/mxnet,luoyetx/mxnet,thirdwing/mxnet,zhreshold/mxnet,thirdwing/mxnet,mbaijal/incubator-mxnet,jiajiechen/mxnet,stefanhenneking/mxnet,szha/mxnet,Prasad9/incubator-mxnet,xcgoner/dist-mxnet,tlby/mxnet,weleen/mxnet,TuSimple/mxnet,coder-james/mxnet,ykim362/mxnet,rishita/mxnet,gautamkmr/incubator-mxnet,sergeykolychev/mxnet,rahul003/mxnet,eric-haibin-lin/mxnet,gautamkmr/incubator-mxnet,Northrend/mxnet,stefanhenneking/mxnet,kkk669/mxnet,indhub/mxnet,Ldpe2G/mxnet,DickJC123/mxnet,larroy/mxnet,likelyzhao/mxnet,mbaijal/incubator-mxnet,leezu/mxnet,jiajiechen/mxnet,TuSimple/mxnet,madjam/mxnet,gautamkmr/incubator-mxnet,lxn2/mxnet,likelyzhao/mxnet,coder-james/mxnet,larroy/mxnet,pluskid/mxnet,reminisce/mxnet,Guneet-Dhillon/mxnet,leezu/mxnet,Northrend/mxnet,jiajiechen/mxnet,fullfanta/mxnet,sxjscience/mxnet,Prasad9/incubator-mxnet,nicklhy/mxnet,danithaca/mxnet,dmlc/mxnet,lxn2/mxnet,larroy/mxnet,indhub/mxnet,stefanhenneking/mxnet,indhub/mxnet,xcgoner/dist-mxnet,rishita/mxnet,nicklhy/mxnet,formath/mxnet,jermainewang/mxnet,sxjscience/mxnet,arikpoz/mxnet,Prasad9/incubator-mxnet,solin319/incubator-mxnet,eric-haibin-lin/mxnet,apaleyes/mxnet,Northrend/mxnet,jamesliu/mxnet,madjam/mxnet,ShownX/incubator-mxnet,wangyum/mxnet,luoyetx/mxnet,rahul003/mxnet,sxjscience/mxnet,CodingCat/mxnet,vikingMei/mxnet,ShownX/incubator-mxnet,yajiedesign/mxnet,reminisce/mxnet,wangyum/mxnet,sergeykolychev/mxnet,ShownX/incubator-mxnet,piiswrong/mxnet,pluskid/mxnet,reminisce/mxnet,crazy-cat/incubator-mxnet,coder-james/mxnet,danithaca/mxnet,szha/mxnet,gautamkmr/incubator-mxnet,tlby/mxnet,jermainewang/mxnet,saurabh3949/mxnet,DR08/mxnet,thirdwing/mxnet,hesseltuinhof/mxnet,szha/mxnet,tlby/mxnet,precedenceguo/mxnet,weleen/mxnet,ZihengJiang/mxnet,Prasad9/incubator-mxnet,kevinthesun/mxnet,LinkHS/incubator-mxnet,ForkedReposBak/mxnet,ptrendx/mxnet,ShownX/incubator-mxnet,yajiedesign/mxnet,LinkHS/incubator-mxnet,piiswrong/mxnet,ForkedReposBak/mxnet,EvanzzzZ/mxnet,kevinthesun/mxnet,yajiedesign/mxnet,gautamkmr/incubator-mxnet,fullfanta/mxnet,rahul003/mxnet,danithaca/mxnet,pluskid/mxnet,hotpxl/mxnet,yajiedesign/mxnet,xcgoner/dist-mxnet,EvanzzzZ/mxnet,leezu/mxnet,Guneet-Dhillon/mxnet,pluskid/mxnet,yuruofeifei/mxnet,eric-haibin-lin/mxnet,eric-haibin-lin/mxnet,kkk669/mxnet,xcgoner/dist-mxnet,ykim362/mxnet,vikingMei/mxnet,weleen/mxnet,coder-james/mxnet,smolix/incubator-mxnet,solin319/incubator-mxnet,leezu/mxnet,rishita/mxnet,dmlc/mxnet,piiswrong/mxnet,navrasio/mxnet,danithaca/mxnet,crazy-cat/incubator-mxnet,kevinthesun/mxnet,antoan2/incubator-mxnet,DickJC123/mxnet,reminisce/mxnet,larroy/mxnet,tornadomeet/mxnet,sergeykolychev/mxnet,szha/mxnet,solin319/incubator-mxnet,Mega-DatA-Lab/mxnet,tlby/mxnet,DR08/mxnet,ykim362/mxnet,mbaijal/incubator-mxnet,nicklhy/mxnet,Ldpe2G/mxnet,stefanhenneking/mxnet,Ldpe2G/mxnet,likelyzhao/mxnet