Spectators cannot know player's playerNumber before it's first updatePosition()

When the game gets rolled, spectators should be notified from each player's playerNumber to place them on the correct start position;

Currently the first time you know someone's playerNumber is when he calls updatePlayer, this method carries both it's playerID and playerNumber.

Proposed fix:
Either
 - already hand out playerNumbers with the playerJoined() method or
 - broadcast playerNumbers together with playerIDs to all spectators when the game gets rolled