Using django-markwhat as a drop-in replacement for ``django.contirb.markup``

This patch fixes #102

Using django-markwhat as a drop-in replacement
for ``django.contirb.markup`` since it's deprecated.

**From django-markwhat docs**

Extracted from [Django 1.4 since markup deprecation](https://docs.djangoproject.com/en/dev/releases/1.5/#django-contrib-markup)

**Supported Python versions**

* Python 2 (2.7)
* Python 3 (3.2, 3.3, 3.4)
* PyPy