Clone the Joind.In plugin to broadcast to Twitter when a talk is fixed

[JonTheNiceGuy]

Given the issue we have with #119, it might be useful to have a straight broadcast for fixed talks.

We already have this functionality in the Joind.In plugin (in /classes/plugins) so if we duplicate this plugin, and amend the request that is sent, it might reduce the requirement to have the Glues in situ, until we can clear up that whole thread.