0.7.0: Add test coverage. Closes #6 (#7)

* Add test coverage. Closes #6

* Install coverage in testing.

* Only support Django 1.7 and later

* Update setup.py

* Don't enforce coverage percentage in testing.

* Add .codecov.yml

* yapf

* Update codecov settings.

* Update codecov settings.

* add branch coverage.

* Move settings file into the tests directory.

* Add settings module docstring.