* Add Meta.fields = '__all__' to serializer classes where required.
* Add explicit on_delete=models.CASCADE to ForeignKey fields.
* Use '.remote_field' and '.model' in preference to '.rel' and '.to' when inspecting model fields.
* Use new value_from_object in preference to internal _get_val_from_obj
* Get rid of runtests.py
* Moved test code from rest_framework/tests and rest_framework/runtests to tests
* Invoke py.test from setup.py
* Invoke py.test from Travis
* Invoke py.test from tox
* Changed setUpClass to be just plain setUp in test_permissions.py
* Updated contribution guideline to show how to invoke py.test