Empty django app

Here's an empty django application with a project called ``stagecraft`` and a single app called ``datasets``. 

- Has modular requirements and settings (see ``DJANGO_SETTINGS_MODULE=stagecraft.settings.staging`` etc)
- Has an ``apps/`` and ``libs/`` directory
- Has the django admin app turned on at ``http://localhost:<port>/admin/``
- Talks to a postgresql database on preview, staging and production
- Tests run and pass in Travis (one dummy test in datasets app)
- Tests pass in both Python 2.7 and 3.3
- Has a README
- Has a LICENCE (MIT)

Lots of inspiration from [http://www.deploydjango.com/django_project_structure/](http://www.deploydjango.com/django_project_structure/).

See https://www.pivotaltracker.com/story/show/63957678