v0.11.0

This release includes a major re-haul of MongoEngine's code quality and introduces a few breaking changes. It also touches many different parts of the package and although all the changes have been tested and scrutinized, you're encouraged to thoroughly test the upgrade.

First breaking change involves renaming ConnectionError to MongoEngineConnectionError. If you import or catch this exception, you'll need to rename it in your code.

Second breaking change drops Python v2.6 support. If you run MongoEngine on that Python version, you'll need to upgrade it first.

Third breaking change drops an old backward compatibility measure where from mongoengine.base import ErrorClass would work on top of from mongoengine.errors import ErrorClass (where ErrorClass is e.g. ValidationError). If you import any exceptions from mongoengine.base, change it to mongoengine.errors.

Lastly, we fixed absent rounding for DecimalField when force_string is set (#1103).