tentative working Django 1.7.1 (bug 935538)

* wip don't merge
* removed funfactory and test_utils

- [x] tests seem a bit slower, mocking might be failing
- [x] need to check on the django-tastypie pinning
- [x] need to run baked
this can be a list? Don't we need to raise just the first error, like ``raise ValidationError(result.errors[0])`` ?