Fix broken doctests
Merge pull request #1175 from frewsxcv/patch-2

Fix broken sphinx docs, thanks @frewsxcv
Updated deprecated manage.py code, added authorization tests to tox.
Enabled customuser tests in tox, fixed customuser tests, changed run_all_tests.sh to work with all versions of Django.
Merge pull request #1140 from SeanHayes/test-enhancements

Test enhancements to make your life easier.
Added failing test case when a non-null field is omitted.
ApiFieldError is now raised when a not-null field is missing.