The previous model didn't really map to how Indra handles objects:
In Indra Local IDs are only really used to look up the FullID, and
that's used to look at a global object list.
This moves to a model where the world (Session) owns the object, and
objects can be freely moved between regions without killing the world's
reference to it.
The two ID design for objects was a mistake in my opinion, but whatever.
