`app_name` is no longer valid on Django 1.8 (tested with 5b1fb0a75d6961d78ba68c72008f1cc535f9689a), and was never defined as public API in the docs, so presumably we want the `name` always
`get_query_set` disappears in Django 1.8 (tested with 5b1fb0a75d6961d78ba68c72008f1cc535f9689a), so we need to smash in a duplicate method going forward.