Blender Git Loki

Workbench: Speed up fo scene with many duplis

The ObjectID pass was generating per material per dupli a specific
number for the outline what results in a GPU context switch. In spring scene
01-050 a scene with many trees (duplis) generated 28000 GPU materials.

Now only new materials are created when objectid pass is enabled. Also
added a hard limit to the number of objects for the objectid pass (255)
Basically the outline between objects will not be drawn, but it will be
very hard to detect them also.

Also fixed for XRay mode.