CONNT-25: Updating appliction and project to use Django 1.6.x:

- Fixed tests to denote that ordering is not important in a number of
queryset tests.
- Replaced deprecated parameter name mimetype with content_type in views.
- Updated development requirements and setup script to depend on Django 1.6.x.
- Removed requirement for django-discover-runner, which is now incorporated
into Django itself and works out of the box.
- Updated development requirements to include pytz (needed for USE_TZ = True
setting).