Added double precision checks in opencl
Added double precision checks in opencl

Added sanity checks for all create*Array functions in opencl backend
to report an error to the user if they try to create double precision
arrays on devices which doesn't have that capability.

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