* Add Django 2.0 compatibility testing
* Drop Django 1.8, 1.9, 1.10 and Python 3.3 support
* Move documentation into README, and standardize layout
* Convert CI and coverage to CircleCi and CodeCov
* Add PyPi-compatible long description
* Bump minimum required version of pinax-images to v3.0.0 for Django 2.0 compatibility