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)
So where it potentially gets weird is when you want to call something by a different name than badgekit-api does.  This is actually happening with Award (badgekit-api's instance) and, more significantly, with Team vs. "issuer".  Granted, there's no reason we couldn't just make Award's verbose_name be "instance", but it feels a little odd.