It changes the following things:
* Changes the counts in the PStatFrameData from uint16 to uint32, since I was hitting the value limit in some heavy frames with Python profiling enabled - no good reason for this limitation, so this allows removing it later
* Adds a T_expire_thread message, which I can use later to fix#450
These features are not used on the client side, but will be used on master. Adding these changes here now makes it possible to use a master client with a 1.10.13 version of the server (can be useful if you can't compile Panda on the host).
Useful for uniquely identifying the process in a situation where multiple clients on the same host connect with the same server.
New version bump is not necessary, as old servers should just ignore the extra field in the datagram.