Fix too much recursion error during update_location_tree. Don't traverse...

... descendents during the all-locations update. Actually disable update_location_tree during prepopulate. Add tests for update_location_tree.
I thought so too, but wasn't going to argue.  Only put it in as it sounded like that's what you were asking for.  ;-)

Ok, I'll put in the above instead (soon as I wake up).

If PR semantics have changed, and a squashed commit pushed with --force does not get into the PR, then it may be better just to add it as a separate commit.