Adding first-pass at tests
Adding first-pass at tests

Includes testing:
* Setting PPOI
* PPOI Validation
* Resized paths
* Filtered paths
* Caching integration
* create_on_demand setting and functionality
* image warming

respondcreate/django-versatileimagefield,theskumar/django-versatileimagefield,WGBH/django-versatileimagefield,respondcreate/django-versatileimagefield,WGBH/django-versatileimagefield,theskumar/django-versatileimagefield,WGBH/django-versatileimagefield,respondcreate/django-versatileimagefield,theskumar/django-versatileimagefield