The server acts as a referee of the game, and also ties the players 
together in a game.

- Help the players set up their games.
- Keep track of all vehicles and the game world.
- Communicate the positions of other tanks to all players.
- Make sure all sent moves are possible.
- Verify if requested kills are valid.
- Mediate communication between players.
- Keep track of victory conditions, and end the game when they are met.
- Manage all issues regarding air and artillery support.

The server needs a "master" virtual world to be able to make decisions as
per the points listed above.