Wagtailnest

- Use dj-core-drf's 'defaults' extras install option
- Update for dj-core-drf 0.0.7
- Fix bug when getting values from QueryDict

- Update for dj-core-drf 0.0.6
- Fix bug in Image endpoint modifying immutable data

- Fix bug in `skeleton_data` using old settings

- Update for dj-core 0.0.6
- Add wagtailnest to apps if not detected by dj-core

- Add .pyup.yml
- Update user forms for wagtail 1.12
- Move dependencies onto dj-core-drf
- Add LICENSE, CHANGELOG.md
- Change setup.py to use requirements-production.txt
- Remove email, tests modules from package

- Remove requirements.txt, local-dev requirements
- Split paragraphs in README