Reverting r4567

This commit broke Edit Linked Library for non-group linked assets as well as using the add-on without loading a new instance of Blender.



git-svn-id: https://svn.blender.org/svnroot/bf-extensions/contrib@4568 96b784f8-4ae3-dd11-aff7-0030488c597c
[TextureAtlas] Removed UV_Editing screen.  Added 8k, 16k textures by request.

git-svn-id: https://svn.blender.org/svnroot/bf-extensions/contrib@4569 96b784f8-4ae3-dd11-aff7-0030488c597c