Multiplayer and win condition modularity

First version of online multiplayer! Run gamehost.py to set up a server
(type localhost for host name if you want a lan server or nothing if you
want a wan one) and gameclient for anyone that wants to connect to
someone who is hosting. Very basic but allows the host to play with the
first person to connect.

Also made checking of win conditions a separate function so they are
easier to add.