Django 1.6 support

CHUNK_SIZE has been removed from Django, so set it ourself if it can't
be imported.
Run travis tests on django dev
assertQuerysetEquals requires an ordered queryset
Increase version and add django 1.6 support to the changelog
Merge pull request #35 from fusionbox/django1.6

Another fix for Django 1.6 support

This addresses the removal of CHUNK_SIZE due to https://code.djangoproject.com/ticket/18702 in django/django@70679243d1786e03557c28929f9762a119e3ac14