reworked APIException, pushing some of the status_code and detail management up.  Also, makes the APIException useful in isolation (defaults to status code 500)
Testing nested serializers with models that have str foreign key references.
Move serializer import to top-level causes test error
Add a sanity check to avoid running into unresolved related models.
Move models.resolve_model to serializers._resolve_model
Merge branch 'master' of git://github.com/cguethle/django-rest-framework into cguethle-master
Move ImportingModelSerializerTests and add comments.
Minor cleanup
Merge branch 'testing-nested-serializers' of git://github.com/dustinfarris/django-rest-framework into dustinfarris-testing-nested-serializers
Minor tweaks