Better treatment for namespace roots

[brandond]

Namespace roots are currently displayed as just a regular unselectable top-level folder, and they and their children are just sorted in with the normal list of folders.

It would be nice if there was some indication (a special icon perhaps) of the special status of the root folder, and if it was sorted specially in the folder list. I'm not sure if it belongs at the top, or bottom, or what, though.