add pytz to tox environments
add django 1.7 environments to tox
add explicit MIDDLEWARE_CLASSES to runtests.py to silence warning in django 1.7
Add default to serves_hot_dogs in test models, to silence warning in django 1.7
rename get_live_query_set to get_live_queryset and get_query_set to get_queryset to fix deprecation warnings in django 1.7
add explicit 'fields' param to forms in tests, to avoid deprecation warnings on django 1.7
Recognise a queryset parameter on get_prefetch_queryset, to fix failure on Django 1.7
Support custom querysets on prefetch_related
changelog entry for django 1.7 support