Blender Git Loki

Cycles: Report error to the blender using report API

This way when something goes wrong in Cycles (for example out of VRAM, timelimit
launching the kernel etc) we'll have a nice report in the Info space header.

Sure it'll be nice to have mention of error in the image editor's information
line, but that's for the future.

This fixes T42747: "CUDA error" appears only momentarily, then disappears