Fix issue with auto-generated group names
Removed unused function
Added support for setup.py test
Loose the permission requirements for site admins (change user is enough).

Also:
* add two new unit tests
* remove some unused imports
Handle case in which a site admin doesn't have any sites and allow the user add form ONLY to superusers
Allow site admins access to the user setup page
Changes to the role permissions are auto-reflected to all generated global page permissions
Changes to the base group permissions are auto-reflected to all site specific auto-generated groups