Tf2 republisher service

Change TFClient to use the new version of tf2_web_republisher (see RobotWebTools/tf2_web_republisher#15 and RobotWebTools/tf2_web_republisher#16 )

Travis job will fail until the new tf2_web_republisher is propagated to the apt sources. Sorry about that.
You don't need to bind here, [`EventEmitter` will call in the context of `this`](https://github.com/asyncly/EventEmitter2/blob/master/lib/eventemitter2.js#L317)