Move player colors and terrain colors to the model

[Trilarion]

For now it's better to concentrate all knowledge in the model. As it is currently the client decides how to color players and terrains but that only works if the model never changes the order of the players and the terrain. That is vulnerable. On the other hand it allows clients to have different skins/looks independent of the model. However, since the client's look will change anyway substantially, concentrate it all in the model for now and make the client "skinnable" later on.