edx / opaque-keys / 1047

96%

master: 96%

Pull #119

travis-ci

Restore [django] extra

This also changes the purpose of `django.in` from being a "core + django
+ django" deps collection to just being the extra deps required for
django support.

- Modifies Tox/Travis configs. The pytest-pyNN test envs were breaking
  since they didn't specify a Django version, and I removed them.
- Puts Tox and Travis into  sync on which test environments to use.
- Moves pytest-django dependency from django.in to test.in

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