check OpenCL fnc return value calls fnc( args )
check OpenCL fnc return value easy wait_list and event passes
check error code after OpenCL fnc call calls fnc( args, &retcode )
check error code after OpenCL fnc call easy wait_list and event passes
check error code and throw exception if it not CL_SUCCESS
base classes, functions, public imports,
loadCL load DerelictCL with version 1.2