FourPlayer is a sample game, which demonstrates the seating properties
of a four-player game. It has exactly four seats, all of which must be
occupied to begin the game.
Sending sit(self) with no seat ID has the default
behavior: you are placed in the first unoccupied seat. If no seat is
unoccupied, the call fails.
Seat IDs
north
south
east
west
RPCs
game.win()
-- The first client to send this wins the game.