Release 2.11.0

Featuring:

* [Update require('hubot') to also export Message in addition to its subclasses](https://github.com/github/hubot/pull/837) - cc @kballard https://github.com/slackhq/hubot-slack/pull/133 
* [Add options argument to robot.http](https://github.com/github/hubot/pull/836) cc @rgbkrk @johntdyer @MacKeeper  https://github.com/github/hubot/pull/612
* [Handle a script not exporting a function](https://github.com/github/hubot/pull/835) c @lajlev @MrSaints #829