Remove use of South from IXDjango command

We're no longer using South with Django 1.7.

Also start making our code Py3k compatible.
Pylint fixes
Update README

[skip ci]
Update pre-commit hook from ISS3
Add pylint mccabe to deps
Merge pull request #16 from infoxchange/django-1.7

Remove use of South from IXDjango command