				MULTI-PLAYER

This file attempts to deal with the problem of multi-player
xtank across a modem between two personal computers.


The main restriction is data transfer speed (approximately 1200 bits/second)
of the modem.  This requires an incredibly space efficient representation
for the events that occur each frame in the game.  Small deltas must
be passed, instead of the entire state of the screen.  This requires
that large amounts of data be stored on both computers.  Both computers
will be doing duplicate processing, to decrease the amount of information
that needs to be sent back and forth.

The only viable model to use is a server-client one.
Clients control one player.  Server controls one player and many
robots.  Server is also responsible for adding in new robots/players.
Everyone has full state of the game.

Clients send all actions to the server.
Server sends all actions to each client.
Processing and display occur.

Actions are passed back an forth.  This is done with opcode+data format.
Need a NO_ACTIONS opcode (a common occurrence)
Heavily used opcodes should be shorter.
Angles represented by 16 bits.
Vehicles represented by as many bits as necessary.

No need to send vehicle id's from client to server or vice-versa,
since we can send the information in a specific order (lowest combatant
to highest).
