Blender Git Loki

Cleanup Collada: changed import stage names for better reading.

The Collada Importer processes the imported files twice. It is still
not clear to me why it needs to do that. However i renamed the
Import stages for now to clarify a bit what really happens:

General -> Fetching_Scene_data
Controller -> Fetching_Controller_data

This change makes it more clear that when the controller data is
fetched these methods are not needed. Before it was much harder
to understand what this is all about.