Initial commit of badge model

This contains a slightly (though increasingly as time goes on) customized version of the django-roa module, used to allow Django models to be represeted on a remote REST API.  (In this case, badgekit api)
Thinking about it, would be nice if you could utilize the standard Django meta information for this - like a slugified version of [`verbose_name`](https://docs.djangoproject.com/en/dev/ref/models/options/#verbose-name) and [`verbose_name_plural`](https://docs.djangoproject.com/en/dev/ref/models/options/#verbose-name-plural) perhaps.