Add complex acos
Add complex acos

marbre/arrayfire,9prady9/arrayfire,ghisvail/arrayfire,victorv/arrayfire,umar456/arrayfire,ghisvail/arrayfire,munnybearz/arrayfire,ghisvail/arrayfire,merlin-ext/arrayfire,munnybearz/arrayfire,9prady9/arrayfire,victorv/arrayfire,munnybearz/arrayfire,shehzan10/arrayfire,arrayfire/arrayfire,marbre/arrayfire,marbre/arrayfire,arrayfire/arrayfire,arrayfire/arrayfire,shehzan10/arrayfire,merlin-ext/arrayfire,9prady9/arrayfire,ghisvail/arrayfire,umar456/arrayfire,umar456/arrayfire,arrayfire/arrayfire,marbre/arrayfire,shehzan10/arrayfire,umar456/arrayfire,merlin-ext/arrayfire,merlin-ext/arrayfire,victorv/arrayfire,victorv/arrayfire,9prady9/arrayfire,shehzan10/arrayfire