Fix tests for django 1.6 and 1.7

Hi!

* For django 1.6, I think we need to set ``object_list`` view attribute before calling ``get_context_data`` instead of passing it as a kwarg because of the evolution of ListView.get_context_data first line in django1.6 : 

    - queryset = kwargs.pop('object_list')
    + queryset = kwargs.pop('object_list', self.object_list)

* For django 1.7, we need to specify MIDDLEWARE_CLASSES and run django.setup()