Add Django as requirement to setup.py
Add Django as requirement to setup.py

As django is imported by the library and is a hard runtime requirement,
it should be listed as a requirement in setup.py for completeness.

jnns/django-import-export,daniell/django-import-export,PetrDlouhy/django-import-export,copperleaftech/django-import-export,django-import-export/django-import-export,django-import-export/django-import-export,jnns/django-import-export,daniell/django-import-export,daniell/django-import-export,bmihelac/django-import-export,jnns/django-import-export,copperleaftech/django-import-export,copperleaftech/django-import-export,django-import-export/django-import-export,PetrDlouhy/django-import-export,PetrDlouhy/django-import-export,daniell/django-import-export,django-import-export/django-import-export,bmihelac/django-import-export,copperleaftech/django-import-export,bmihelac/django-import-export,jnns/django-import-export,bmihelac/django-import-export,PetrDlouhy/django-import-export