Added ConsoleCommand, and an example to go with it

OpenRA.Mods.RA/TraitsInterfaces.cs

@@ -48,4 +48,5 @@ namespace OpenRA.Mods.RA
 	public interface INotifyTransform { void OnTransform(Actor self); }
 	public interface INotifyTransformed { void OnTransformed(Actor toActor); }
 	public interface INotifyAttack { void Attacking(Actor self, Target target, Armament a, Barrel barrel); }
+	public interface INotifyChat { bool OnChat(string from, string message); }
 }