-----
Changes:
- New admin_generator, can generate a admin.py file from models
- Improvement: sqldiff, use the same exit codes as diff uses
- Improvement: sqldiff, add support for unsigned numeric fields
- Improvement: sqldiff, add NOT NULL support for MySQL
- Improvement: sqldiff, add proper AUTO_INCREMENT support for MySQL
- Improvement: sqldiff, detect tables for which no model exists
- Improvement: travis.yml, add pypy to tests
- Fix: sqldiff, fix for mysql misreported field lengths
- Fix: sqldiff, in PG custom int primary keys would be mistaking for serial
- Fix: sqldiff, use Django 1.7 db_parameters() for detect check constraints
- Fix: update_permissions, Django 1.7 support
- Fix: encrypted fields, fix for Django 1.7 migrations