UUID! (For all player-related tasks except if a name→UUID conversion is needed)

[AmauryCarrade]

Use UUIDs for all player-related things, except getting a player object from a name typed in a command (for this point, I'll wait the 1.8 version of Bukkit, and the standardized way to do this, because there isn't anything stored.

• [x] UUID in the UHTeam class.
• [x] UUID in the UHGameManager class:
  • players (waiting for the name→UUID conversion API);
  • alivePlayers;
  • spectators;
  • deathLocations;
  • deadPlayersToBeResurrected (waiting for the name→UUID conversion API).
• [x] UUID in the UHFreezer class.