Basic message queueing
* Fixed lots of bugs in earlier implementation (serialization errors, NPEs)
* Added a PriorityQueue of messages to be sent
* Added prepended sessionId to clientId, to circumvent the possibility of identity forgery
* Client now automatically reconnects, informing the server about last received message timestamp
* Server now does not drop clients forcefully, instead informs them that they wont be served as they are now
* There is no longer terminate command, instead we inform client to do the reset