Blender Git Loki

patch [#23212] Python api for Nodes
from Dan Eicher (dna)

This allows automated node tree creation and editing.

developer note, made some changes to the patch.
- removed incorrect use of container_of(), GCC only also, search for the scene instead.
- commented socket min/max access, these are internal use only as far as I can tell.
- commented group/ungroup functions, these use the selection context and are not really data level functions.
- use remove() rather then delete()