Added a server managed notion of which client is controlling the game.

Doing this on the client, while theoretically possible, is more complex. We
have a server, we use it to provide commonly needed services, the assignment of
a single client to control the game is a commonly needed service. This also
matches the way other services like turn change and game start and end are
implemented.

A side note: the client-side code was not properly handling disconnected
players, which the server code properly handles.


git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@224 c613c5cb-e716-0410-b11b-feb51c14d237

src/as/com/threerings/ezgame/StateChangedEvent.as

@@ -34,6 +34,9 @@ public class StateChangedEvent extends EZEvent
     /** Indicates that the game has transitioned to a ended state. */
     public static const GAME_ENDED :String = "GameEnded";
 
+    /** Indicates that a new controller has been assigned. */
+    public static const CONTROL_CHANGED :String = "ControlChanged";
+
     /** Indicates that the turn has changed. */
     // TODO: move to own event?
     public static const TURN_CHANGED :String = "TurnChanged";