Security

The comments module should be secure enough to follow through any security issue that's to be arise.

References / Plan:
1. [Django security module](https://docs.djangoproject.com/en/1.8/ref/middleware/#module-django.middleware.security)
2. [Some alternate django security packages](https://www.djangopackages.com/grids/g/security)

Also, revisiting the [django-contrib-comments](https://github.com/django/django-contrib-comments) security guidelines to come up with a powerful security module.