Removed deprecated contrib.csrf app.

from django.middleware.csrf import CsrfMiddleware, CsrfViewMiddleware, CsrfResponseMiddleware

from django.views.decorators.csrf import csrf_exempt, csrf_view_exempt, csrf_response_exempt

import warnings

warnings.warn("This import for CSRF functionality is deprecated.  Please use django.middleware.csrf for the middleware and django.views.decorators.csrf for decorators.",

              DeprecationWarning

              )