Player movement parameters should be sent over the wire

[jdolan]

As a server admin, I'd like to run a Quake themed server that features Quake level remakes and QuakeWorld style player movement. To do this, I'd like to be able to specify all player movement parameters (friction, acceleration, air acceleration, etc) via console variables. The server should send these to the client as a custom packet type if and when they change, so that client side prediction will match the server.

[Paril]

In Q2pro, there's a special "pmp" struct that handles these things that are sent through special packets. We can just do the same here.