Rework client/server replication so that there's no client ID required (a la BigWorld), instead the client and server go through a handshake where the client creates a GUID, gives it to the server, and is given a short session ID to use for all future communication.

Also, rework the communication a bit so that receiving a UDP packet has an option to only process the header and command blobs. This is a small hack to get around what isn't a great design (i.e. not having a single starting point to handling the packet).