Blender Git Loki

Depsgraph: Quick and ugly fix for missing updates in the viewport

Previously viewport will skip updates on changing lamp/materials because
old system wasn't really working good enough with drivers using variables
from node tree.

Now it just works, but it's quite tricky to know if viewport needs to be
updated or not, so let's just update it if new depsgraph is used. Could
become more granular later.