Disable C# 6 features until CI/build system updated
Disable C# 6 features until CI/build system updated

With Visual Studio 2015 released today (woo hoo!), I expect we're going to see the number of contributors using VS2015 and C# 6 increase, which is a good thing.  Unfortunately, our current build / CI system is currently limited to using the C# 5 compiler.  Speaking from experience, this makes for a frustrating time when one develops a change and everything passes locally, only to submit a PR and find that it fails in CI because a C# 6 feature was being used.

Until we can get our build and CI systems updated to use C# 6 (hopefully very soon), this change simply sets the LangVersion for our C# projects to C# 5 so that, even when using VS2015, attempting to build locally with C# 6 features will fail to compile.  This won't prevent all possible dependencies on C# 6, but it will avert most.

nbarbettini/corefx,khdang/corefx,Chrisboh/corefx,stone-li/corefx,rajansingh10/corefx,rubo/corefx,jcme/corefx,dkorolev/corefx,bpschoch/corefx,pgavlin/corefx,dotnet-bot/corefx,ptoonen/corefx,Jiayili1/corefx,comdiv/corefx,JosephTremoulet/corefx,elijah6/corefx,elijah6/corefx,twsouthwick/corefx,DnlHarvey/corefx,Alcaro/corefx,nchikanov/corefx,viniciustaveira/corefx,yizhang82/corefx,adamralph/corefx,kkurni/corefx,nchikanov/corefx,the-dwyer/corefx,mellinoe/corefx,DnlHarvey/corefx,YoupHulsebos/corefx,Chrisboh/corefx,billwert/corefx,zhangwenquan/corefx,benjamin-bader/corefx,Jiayili1/corefx,lggomez/corefx,brett25/corefx,dhoehna/corefx,shimingsg/corefx,mmitche/corefx,akivafr123/corefx,parjong/corefx,mafiya69/corefx,PatrickMcDonald/corefx,stone-li/corefx,the-dwyer/corefx,cydhaselton/corefx,yizhang82/corefx,jeremymeng/corefx,jhendrixMSFT/corefx,ViktorHofer/corefx,alexperovich/corefx,parjong/corefx,Priya91/corefx-1,uhaciogullari/corefx,bitcrazed/corefx,comdiv/corefx,bpschoch/corefx,rubo/corefx,seanshpark/corefx,adamralph/corefx,andyhebear/corefx,Ermiar/corefx,stephenmichaelf/corefx,Jiayili1/corefx,billwert/corefx,lydonchandra/corefx,mmitche/corefx,jcme/corefx,manu-silicon/corefx,axelheer/corefx,janhenke/corefx,alexperovich/corefx,shahid-pk/corefx,shmao/corefx,mmitche/corefx,andyhebear/corefx,alphonsekurian/corefx,stone-li/corefx,stormleoxia/corefx,nbarbettini/corefx,gabrielPeart/corefx,krk/corefx,vidhya-bv/corefx-sorting,jhendrixMSFT/corefx,SGuyGe/corefx,pgavlin/corefx,jcme/corefx,VPashkov/corefx,Jiayili1/corefx,ravimeda/corefx,marksmeltzer/corefx,Frank125/corefx,KrisLee/corefx,Chrisboh/corefx,dtrebbien/corefx,CloudLens/corefx,ericstj/corefx,weltkante/corefx,mafiya69/corefx,zhenlan/corefx,thiagodin/corefx,Frank125/corefx,rubo/corefx,fffej/corefx,shrutigarg/corefx,billwert/corefx,scott156/corefx,jhendrixMSFT/corefx,janhenke/corefx,vidhya-bv/corefx-sorting,iamjasonp/corefx,richlander/corefx,anjumrizwi/corefx,ptoonen/corefx,gkhanna79/corefx,ptoonen/corefx,zmaruo/corefx,billwert/corefx,matthubin/corefx,lydonchandra/corefx,weltkante/corefx,mmitche/corefx,chenxizhang/corefx,cnbin/corefx,n1ghtmare/corefx,BrennanConroy/corefx,tijoytom/corefx,lggomez/corefx,tstringer/corefx,nbarbettini/corefx,rahku/corefx,alphonsekurian/corefx,rajansingh10/corefx,twsouthwick/corefx,axelheer/corefx,nbarbettini/corefx,stephenmichaelf/corefx,cydhaselton/corefx,CherryCxldn/corefx,mellinoe/corefx,janhenke/corefx,stone-li/corefx,gregg-miskelly/corefx,heXelium/corefx,weltkante/corefx,ravimeda/corefx,iamjasonp/corefx,rubo/corefx,ravimeda/corefx,690486439/corefx,alphonsekurian/corefx,chaitrakeshav/corefx,mellinoe/corefx,wtgodbe/corefx,dotnet-bot/corefx,vs-team/corefx,lggomez/corefx,gkhanna79/corefx,heXelium/corefx,vs-team/corefx,krk/corefx,ericstj/corefx,alphonsekurian/corefx,janhenke/corefx,CherryCxldn/corefx,shimingsg/corefx,cydhaselton/corefx,manu-silicon/corefx,rjxby/corefx,s0ne0me/corefx,seanshpark/corefx,weltkante/corefx,jcme/corefx,gkhanna79/corefx,alexperovich/corefx,scott156/corefx,khdang/corefx,zhenlan/corefx,Yanjing123/corefx,iamjasonp/corefx,jhendrixMSFT/corefx,ericstj/corefx,tijoytom/corefx,dotnet-bot/corefx,mokchhya/corefx,CloudLens/corefx,pallavit/corefx,marksmeltzer/corefx,cartermp/corefx,rahku/corefx,alexandrnikitin/corefx,manu-silicon/corefx,anjumrizwi/corefx,xuweixuwei/corefx,vs-team/corefx,pgavlin/corefx,vijaykota/corefx,ericstj/corefx,alphonsekurian/corefx,akivafr123/corefx,DnlHarvey/corefx,manu-silicon/corefx,billwert/corefx,VPashkov/corefx,jlin177/corefx,shimingsg/corefx,tijoytom/corefx,tstringer/corefx,stephenmichaelf/corefx,cartermp/corefx,krk/corefx,josguil/corefx,weltkante/corefx,MaggieTsang/corefx,erpframework/corefx,ravimeda/corefx,cydhaselton/corefx,axelheer/corefx,YoupHulsebos/corefx,gregg-miskelly/corefx,twsouthwick/corefx,690486439/corefx,marksmeltzer/corefx,ellismg/corefx,ravimeda/corefx,benjamin-bader/corefx,nchikanov/corefx,nbarbettini/corefx,shrutigarg/corefx,ViktorHofer/corefx,thiagodin/corefx,lydonchandra/corefx,cartermp/corefx,lggomez/corefx,claudelee/corefx,mellinoe/corefx,khdang/corefx,anjumrizwi/corefx,shrutigarg/corefx,Frank125/corefx,cnbin/corefx,wtgodbe/corefx,lggomez/corefx,wtgodbe/corefx,Yanjing123/corefx,Petermarcu/corefx,JosephTremoulet/corefx,s0ne0me/corefx,PatrickMcDonald/corefx,thiagodin/corefx,ravimeda/corefx,jlin177/corefx,mazong1123/corefx,krk/corefx,Petermarcu/corefx,krk/corefx,Priya91/corefx-1,kkurni/corefx,DnlHarvey/corefx,krytarowski/corefx,erpframework/corefx,seanshpark/corefx,elijah6/corefx,CherryCxldn/corefx,shahid-pk/corefx,pallavit/corefx,rajansingh10/corefx,VPashkov/corefx,s0ne0me/corefx,gabrielPeart/corefx,yizhang82/corefx,vijaykota/corefx,richlander/corefx,mazong1123/corefx,manu-silicon/corefx,Jiayili1/corefx,shimingsg/corefx,shmao/corefx,shana/corefx,SGuyGe/corefx,cartermp/corefx,brett25/corefx,lydonchandra/corefx,ellismg/corefx,wtgodbe/corefx,rjxby/corefx,Alcaro/corefx,dsplaisted/corefx,stephenmichaelf/corefx,Ermiar/corefx,pallavit/corefx,richlander/corefx,parjong/corefx,parjong/corefx,ptoonen/corefx,krytarowski/corefx,SGuyGe/corefx,dhoehna/corefx,claudelee/corefx,mafiya69/corefx,larsbj1988/corefx,elijah6/corefx,Petermarcu/corefx,YoupHulsebos/corefx,khdang/corefx,anjumrizwi/corefx,ptoonen/corefx,parjong/corefx,dhoehna/corefx,Yanjing123/corefx,khdang/corefx,zhenlan/corefx,dsplaisted/corefx,nelsonsar/corefx,twsouthwick/corefx,vrassouli/corefx,ravimeda/corefx,shmao/corefx,vidhya-bv/corefx-sorting,alexperovich/corefx,mazong1123/corefx,dhoehna/corefx,huanjie/corefx,rjxby/corefx,dhoehna/corefx,YoupHulsebos/corefx,erpframework/corefx,yizhang82/corefx,jeremymeng/corefx,chaitrakeshav/corefx,kyulee1/corefx,rahku/corefx,JosephTremoulet/corefx,tstringer/corefx,jeremymeng/corefx,krytarowski/corefx,rubo/corefx,mokchhya/corefx,690486439/corefx,chaitrakeshav/corefx,benpye/corefx,jhendrixMSFT/corefx,stormleoxia/corefx,alexandrnikitin/corefx,dtrebbien/corefx,lggomez/corefx,richlander/corefx,nbarbettini/corefx,fffej/corefx,krytarowski/corefx,shana/corefx,s0ne0me/corefx,brett25/corefx,josguil/corefx,jcme/corefx,larsbj1988/corefx,dtrebbien/corefx,CherryCxldn/corefx,stone-li/corefx,chaitrakeshav/corefx,PatrickMcDonald/corefx,tijoytom/corefx,josguil/corefx,Ermiar/corefx,nelsonsar/corefx,dotnet-bot/corefx,mazong1123/corefx,shimingsg/corefx,jlin177/corefx,stormleoxia/corefx,comdiv/corefx,cnbin/corefx,dhoehna/corefx,jeremymeng/corefx,mazong1123/corefx,bitcrazed/corefx,mmitche/corefx,vijaykota/corefx,axelheer/corefx,stephenmichaelf/corefx,n1ghtmare/corefx,Chrisboh/corefx,Frank125/corefx,fffej/corefx,twsouthwick/corefx,zhenlan/corefx,akivafr123/corefx,Petermarcu/corefx,jmhardison/corefx,n1ghtmare/corefx,mafiya69/corefx,rahku/corefx,chenxizhang/corefx,jlin177/corefx,matthubin/corefx,tijoytom/corefx,benpye/corefx,benjamin-bader/corefx,krk/corefx,zmaruo/corefx,gregg-miskelly/corefx,seanshpark/corefx,larsbj1988/corefx,Priya91/corefx-1,fgreinacher/corefx,the-dwyer/corefx,JosephTremoulet/corefx,stone-li/corefx,mmitche/corefx,stephenmichaelf/corefx,CloudLens/corefx,MaggieTsang/corefx,Ermiar/corefx,jcme/corefx,dkorolev/corefx,fgreinacher/corefx,KrisLee/corefx,tstringer/corefx,richlander/corefx,tstringer/corefx,Priya91/corefx-1,josguil/corefx,claudelee/corefx,vs-team/corefx,heXelium/corefx,yizhang82/corefx,ViktorHofer/corefx,uhaciogullari/corefx,billwert/corefx,alexandrnikitin/corefx,gabrielPeart/corefx,weltkante/corefx,bpschoch/corefx,jmhardison/corefx,rahku/corefx,zhangwenquan/corefx,Yanjing123/corefx,dkorolev/corefx,alexperovich/corefx,heXelium/corefx,kyulee1/corefx,ptoonen/corefx,Ermiar/corefx,vidhya-bv/corefx-sorting,Petermarcu/corefx,BrennanConroy/corefx,lggomez/corefx,scott156/corefx,ViktorHofer/corefx,nelsonsar/corefx,viniciustaveira/corefx,Alcaro/corefx,mellinoe/corefx,shmao/corefx,Priya91/corefx-1,jlin177/corefx,YoupHulsebos/corefx,cartermp/corefx,rjxby/corefx,cartermp/corefx,pallavit/corefx,shahid-pk/corefx,shana/corefx,jhendrixMSFT/corefx,mazong1123/corefx,parjong/corefx,matthubin/corefx,kyulee1/corefx,690486439/corefx,mmitche/corefx,rajansingh10/corefx,comdiv/corefx,krytarowski/corefx,mokchhya/corefx,uhaciogullari/corefx,krytarowski/corefx,dkorolev/corefx,benjamin-bader/corefx,mafiya69/corefx,richlander/corefx,axelheer/corefx,shahid-pk/corefx,andyhebear/corefx,pgavlin/corefx,VPashkov/corefx,matthubin/corefx,Priya91/corefx-1,jmhardison/corefx,dhoehna/corefx,Jiayili1/corefx,shana/corefx,wtgodbe/corefx,zhenlan/corefx,vrassouli/corefx,bitcrazed/corefx,iamjasonp/corefx,adamralph/corefx,fgreinacher/corefx,marksmeltzer/corefx,oceanho/corefx,YoupHulsebos/corefx,dsplaisted/corefx,pallavit/corefx,690486439/corefx,iamjasonp/corefx,Petermarcu/corefx,zhenlan/corefx,vrassouli/corefx,ericstj/corefx,dtrebbien/corefx,ViktorHofer/corefx,ptoonen/corefx,wtgodbe/corefx,nchikanov/corefx,fgreinacher/corefx,yizhang82/corefx,Alcaro/corefx,benpye/corefx,mazong1123/corefx,parjong/corefx,KrisLee/corefx,oceanho/corefx,wtgodbe/corefx,BrennanConroy/corefx,bitcrazed/corefx,dotnet-bot/corefx,nchikanov/corefx,mokchhya/corefx,seanshpark/corefx,tijoytom/corefx,shmao/corefx,DnlHarvey/corefx,DnlHarvey/corefx,manu-silicon/corefx,nchikanov/corefx,kkurni/corefx,benpye/corefx,zmaruo/corefx,Jiayili1/corefx,khdang/corefx,gabrielPeart/corefx,Ermiar/corefx,scott156/corefx,gkhanna79/corefx,josguil/corefx,xuweixuwei/corefx,dotnet-bot/corefx,the-dwyer/corefx,brett25/corefx,xuweixuwei/corefx,shmao/corefx,nbarbettini/corefx,stormleoxia/corefx,alexandrnikitin/corefx,pallavit/corefx,kkurni/corefx,vrassouli/corefx,stone-li/corefx,gkhanna79/corefx,marksmeltzer/corefx,zhangwenquan/corefx,oceanho/corefx,mokchhya/corefx,ViktorHofer/corefx,uhaciogullari/corefx,Petermarcu/corefx,ellismg/corefx,cydhaselton/corefx,krk/corefx,viniciustaveira/corefx,benpye/corefx,jhendrixMSFT/corefx,bitcrazed/corefx,chenxizhang/corefx,billwert/corefx,alexperovich/corefx,cydhaselton/corefx,seanshpark/corefx,the-dwyer/corefx,alexperovich/corefx,jmhardison/corefx,twsouthwick/corefx,manu-silicon/corefx,iamjasonp/corefx,ellismg/corefx,zhangwenquan/corefx,twsouthwick/corefx,mafiya69/corefx,stephenmichaelf/corefx,DnlHarvey/corefx,n1ghtmare/corefx,rjxby/corefx,shahid-pk/corefx,janhenke/corefx,MaggieTsang/corefx,PatrickMcDonald/corefx,KrisLee/corefx,shimingsg/corefx,jlin177/corefx,andyhebear/corefx,viniciustaveira/corefx,gkhanna79/corefx,mellinoe/corefx,oceanho/corefx,vidhya-bv/corefx-sorting,JosephTremoulet/corefx,MaggieTsang/corefx,larsbj1988/corefx,alphonsekurian/corefx,YoupHulsebos/corefx,mokchhya/corefx,claudelee/corefx,kkurni/corefx,elijah6/corefx,elijah6/corefx,shahid-pk/corefx,bpschoch/corefx,josguil/corefx,shmao/corefx,ellismg/corefx,huanjie/corefx,MaggieTsang/corefx,janhenke/corefx,cydhaselton/corefx,elijah6/corefx,rahku/corefx,MaggieTsang/corefx,SGuyGe/corefx,Chrisboh/corefx,ericstj/corefx,the-dwyer/corefx,gkhanna79/corefx,gregg-miskelly/corefx,the-dwyer/corefx,akivafr123/corefx,ericstj/corefx,MaggieTsang/corefx,axelheer/corefx,jeremymeng/corefx,dotnet-bot/corefx,fffej/corefx,marksmeltzer/corefx,benjamin-bader/corefx,kkurni/corefx,yizhang82/corefx,huanjie/corefx,ViktorHofer/corefx,CloudLens/corefx,PatrickMcDonald/corefx,Yanjing123/corefx,Ermiar/corefx,benjamin-bader/corefx,SGuyGe/corefx,zhenlan/corefx,tijoytom/corefx,kyulee1/corefx,JosephTremoulet/corefx,shimingsg/corefx,weltkante/corefx,n1ghtmare/corefx,zmaruo/corefx,krytarowski/corefx,marksmeltzer/corefx,rjxby/corefx,JosephTremoulet/corefx,seanshpark/corefx,erpframework/corefx,rjxby/corefx,shrutigarg/corefx,alexandrnikitin/corefx,jlin177/corefx,SGuyGe/corefx,richlander/corefx,thiagodin/corefx,nchikanov/corefx,benpye/corefx,ellismg/corefx,huanjie/corefx,Chrisboh/corefx,cnbin/corefx,tstringer/corefx,iamjasonp/corefx,rahku/corefx,akivafr123/corefx,alphonsekurian/corefx,nelsonsar/corefx