Docs: Update Event Logger protocol. We're now using MessagePack.
EventLogger: Implement MessagePack-to-JSON decoder for new protocol format.
EventSender: Allow sending of new-format events.
ClientAgent: Adjust use of EventSender to send new MessagePack-formatted logs.
EventLogger: Bring back "new log file" logs.
Merge pull request #215 from Astron/enhancement/eventlogger-msgpack

Switch EventLogger protocol to MessagePack