The ability to save events, and later replay them

In order to facilitate better testing ( especially when we get to performance testing ), the ability to save all events to a replay logfile, which can then in turn be fed into ember to produce the same results. Ideally, this should capture all user input, all messages sent to the server, and all responses. Ember could then later be invoked to replay this file and produce the exact same results. This will greatly help with troubleshooting problems, as well as providing a consistent method of measuring performance tuning ( allowing a comparison against known measured set of actions )