order validation; don't hold refs in local orders; etc

OpenRa.Game/UnitOrders.cs

@@ -1,10 +1,8 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
+using IjwFramework.Types;
 using OpenRa.Game.GameRules;
 using OpenRa.Game.Traits;
-using IjwFramework.Types;
-using System.Diagnostics;
 
 namespace OpenRa.Game
 {
@@ -12,6 +10,12 @@ namespace OpenRa.Game
 	{
 		public static void ProcessOrder( Order order )
 		{
+			if (!order.Validate())
+			{
+				/* todo: log this if we care */
+				return;
+			}
+
 			switch( order.OrderString )
 			{
 			case "Move":