* Remove a couple of functions from the group libs that are only used in one or two places:
 - get_owned_groups was only used on user/view and for the sideblock showing the groups you owned. We're going to show more than that now, meaning the function is wasted indirection for the one remaining place it would be used.
 - get_tutor_groups was only used on user/view, and has been broken by the group schema changes.
* Fix adding users to controlled communities. Still have to provide the ability to do this by dropdown.
* Fixed a bug caused by my misunderstanding of how (array) false works - it seems to make an array with 'false' as one value.