Blender Git Loki

Bugfix #21916: Baking NLA strips doesn't group transforms

- Added an optional string arg to struct.keyframe_insert() and struct.keyframe_delete() for the name of the group to add the keyframes to (for newly created F-Curves), instead of doing this as post process.

- Added error prints to the RNA function for setting an F-Curve's group. The old way of setting the groups afterwards couldn't be used anymore, since there was no way to find the action the F-Curve belonged to. This is necessary if the F-Curve list is to be kept in a valid state, since adding to any random group that may not be in the same Action does not work well. There were other issues with the list being iterated over changing while it was still being iterated over too...

TODO:
Find a way to allow the iterator there to still work ok?