Merge pull request #1 from scholrly/master

Merge new graph_auth
Need django.contrib.auth.models.User's get_username method

Sometimes it throws an exception.
With a grep I see it's needed in admin interface too.
Update auth.rst
Merge pull request #216 from tonjo/master

Small updates
Merge branch 'master' of github.com:scholrly/neo4django

Conflicts:
	neo4django/graph_auth/models.py