Prevents orphaned maplayers from breaking the map detail views

TODO: orphaned maplayers should be properly removed
Merge pull request #804 from MAPC/patch-804

Prevents orphaned maplayers from breaking map detail views
Merge pull request #803 from MAPC/master

Adds CSS cursor pointer for *_list pages.
fixed notification for updatelayers
Merge branch 'master' into masshealth
cleaning up settings after master merge
activating notifications after fixes from master
Adds fallback to default auth backend in has_perm permission lookup function
adds check for owner attr in obj in has_perm permission lookup
adds extra requirements file for masshealth
adds last_modified and user field to masshealth heroes model class
adds last_modified and user field to masshealth programs model class
adds last_modified and user field to masshealth places model class