Use the {% admin_media_prefix %} rather than hardcoding the /static/ url
LUN-880 -- replace ability to add new users with the ability of assigning existing users to sites
LUN-880 -- remove the no longer existing view add_user from urls.py (missed this in the prev commit)
LUN-881 -- proper handling of assigning or un-assigning user roles for the current site
LUN-878 -- When the user clicks 'save and continue editing' the current site is taken into account
LUN-878 -- Also look at the request's HOST header for determining the current working site
LUN-880 and LUN-881 -- Added unit tests for testing POSTing user setup formsets
Merge pull request #2 from pbs/bug-fixes

Various bug fixes: LUN-881, LUN-880, LUN-878
LUN-879 -- When checking for administered sites also check for global page permissions that directly reference the user
Merge pull request #3 from pbs/LUN-879

LUN-879 -- When checking for administered sites also check for global page permissions that directly reference the user
Pretty buttons for the assign/unassign user links
Auto-generated site groups permissions are updated when role group changes.
_get_permissions_dict always returns the same result so it doesn't make sense to call it in every iteration of the for loop
Merge branch 'LUN-877'
LUN-897: added user-role validation.
LUN-889: UserSetup only 4 site admins w/ sites under their control
Merge pull request #5 from pbs/LUN-897

LUN-897: added user-role form validation
Changes based on code review.
Merge pull request #6 from pbs/LUN-889

Lun 889
Both user and role need to be set in a user form.

However, if both user and role are not set, the form validation should pass.
This is why the required=True approach was flawed.