many operators uses Bases, for the python to set operators context python too needs...

many operators uses Bases, for the python to set operators context python too needs to be able to access bases.
- added scene.bases (like scene.objects)
- renamed group create operator.

Example
 scene = bpy.data.scenes[0]
 C = {}
 C["scene"] = scene
 C["selected_editable_bases"] = [scene.bases[2], scene.bases[3]]

 bpy.ops.group.create(C)

Also made operator fake modules not return __call__ (reported by Stani, fixes autocomp. bug)