Implement player stance colors

Adds an option to display actors on radar and
support weapon timers in colors denoting the
diplomatic stance toward the player.

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -203,7 +203,7 @@ namespace OpenRA.Traits
 		bool HasFogVisibility();
 	}
 
-	public interface IRadarColorModifier { Color RadarColorOverride(Actor self); }
+	public interface IRadarColorModifier { Color RadarColorOverride(Actor self, Color color); }
 
 	public interface IOccupySpaceInfo : ITraitInfoInterface
 	{