Bug fix for reductions in CUDA backend
Bug fix for reductions in CUDA backend

- Intra warp reductions now use the volatile keyword

bkloppenborg/arrayfire,victorv/arrayfire,bkloppenborg/arrayfire,pentschev/arrayfire,glehmann/arrayfire,pavanky/arrayfire,pombredanne/arrayfire,jramapuram/arrayfire,pavanky/arrayfire,linan7788626/arrayfire,asifmadnan/arrayfire,ghisvail/arrayfire,ghisvail/arrayfire,asifmadnan/arrayfire,pavanky/arrayfire,munnybearz/arrayfire,9prady9/arrayfire,arrayfire/arrayfire,HolyGeneralK/arrayfire,linan7788626/arrayfire,shehzan10/arrayfire,Keno/arrayfire,shehzan10/arrayfire,hshindo/arrayfire,mrgloom/arrayfire,umar456/arrayfire,asifmadnan/arrayfire,umar456/arrayfire,umar456/arrayfire,unbornchikken/arrayfire,ghisvail/arrayfire,marbre/arrayfire,pombredanne/arrayfire,glehmann/arrayfire,Keno/arrayfire,hshindo/arrayfire,victorv/arrayfire,mrgloom/arrayfire,merlin-ext/arrayfire,mrgloom/arrayfire,0x0all/arrayfire,arrayfire/arrayfire,munnybearz/arrayfire,linan7788626/arrayfire,unbornchikken/arrayfire,hshindo/arrayfire,9prady9/arrayfire,shehzan10/arrayfire,Keno/arrayfire,HolyGeneralK/arrayfire,jramapuram/arrayfire,pavanky/arrayfire,umar456/arrayfire,arrayfire/arrayfire,unbornchikken/arrayfire,victorv/arrayfire,arrayfire/arrayfire,pentschev/arrayfire,hshindo/arrayfire,jramapuram/arrayfire,9prady9/arrayfire,ghisvail/arrayfire,bkloppenborg/arrayfire,marbre/arrayfire,pombredanne/arrayfire,shehzan10/arrayfire,marbre/arrayfire,victorv/arrayfire,merlin-ext/arrayfire,Keno/arrayfire,jramapuram/arrayfire,pentschev/arrayfire,marbre/arrayfire,HolyGeneralK/arrayfire,bkloppenborg/arrayfire,pentschev/arrayfire,merlin-ext/arrayfire,pombredanne/arrayfire,asifmadnan/arrayfire,linan7788626/arrayfire,9prady9/arrayfire,unbornchikken/arrayfire,merlin-ext/arrayfire,mrgloom/arrayfire,HolyGeneralK/arrayfire,0x0all/arrayfire,munnybearz/arrayfire