Prepare v2.0.0 for release

Prepare v1.4.0 for release

- Added support for Django 2.0

- Added support for Django 1.11 and Python 3.6
- Dropped support for PyPy and PyPy3

Prepare v1.2.1 for release

Prepare v1.2.0 for release

Prepare v1.1.1 for release

Prepare v1.1.0 for release

Prepare v1.0.0 for release

Prepare v0.4 for release

Prepare v0.3 for release