MySQL-python hasn't really been maintained in a while, is not

compatible with Python 3, and isn't really getting a whole lot of

updates. The successor to this package, which is fully API-compatible,

has wheels, and is compatible with Python 2.7 and 3, is mysqlclient.

This switches our development dependency over to that.

Successfully installed via pip and easy_install on Python 2.7, 3.4,

3.5, and 3.6. MySQL-specific unit tests passed with this dependency

(as did Django Evolution tests for MySQL, which is a better set of

tests in this case).