Django Evolution 2.0 introduces a new Evolver class for

programmatically synchronizing models to the database and applying

evolutions and migrations. This is now required by Djblets if the

extension framework at all wants to allow for extensions with models.
This replaces shelling out to syncdb/migrate and evolve,

simplifying our code considerably and letting Django Evolution handle

all the hard parts.
It also has a very strong advantage of only managing the apps owned by

the extension, preventing any other apps from ever being affected.

Previously, if there was a new model or evolution introduced somewhere

(by another app, or by Review Board itself), it woud have been

synced/evolved as well, which posed problems at times. Now that we have

greater control, changes to the database (and the stored project

signature) will be minimized.
Unit tests have been updated to work with the new Django Evolution APIs,

and to assume that Django Evolution is present for tests (since we

include this in dev-requirements.txt).
The dependency version has been bumped as well, currently requiring that

the version in the Django Evolution master branch in Git be installed.

Unit tests pass on Django 1.6 and 1.11.