Fix 2 bugs; anon users and preparing nulls.
Merge branch 'master' of github.com:armet/django-armet
Coerce the PK on a model resource.
Active users required.
Deny editing of excluded fields.
Fix bug for 3-state boolean
If you can modify X you can modify it into a state in which you can't modify it.
Merge remote-tracking branch 'origin/master' into topics/paginator