LOW PRIORITY: FEATURE: Add data handling to SimplePush

Allow "data" to be send to actively connected clients. This does NOT store the data, so if a client isn't connected, the data WILL BE discarded.

Also: 

* add unit tests for Update handler
* refactor code to provide framework for adding unit tests for handlers
* removed some extraneous classes that were causing data duplication.
![approved](https://cloud.githubusercontent.com/assets/35755/4687294/1515986c-5653-11e4-925e-2d37232625a8.jpg)