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)

release/scripts/modules/bpy_ops.py

@@ -98,6 +98,8 @@ class bpy_ops_submodule(object):
         '''
         gets a bpy.ops.submodule function
         '''
+        if func.startswith('__'):
+            raise AttributeError(func)
         return bpy_ops_submodule_op(self.module, func)
 
     def __dir__(self):