Blender Git Loki

Added defines for list+number of all operation nodes to depsgraph

The purpose of these defines at toplevel is so that operations
over the nodes do not necessarily require setting up a full
aparatus for performing node traversal.

Also, the nodecount variable provides us with a valuable ability
to cross-check whether all nodes have been evaluated. (Then again,
it doesn't quite work, as not all nodes will be scheduled up)