basic Sync checking. No protocol stuff yet; just checks that input events are well-behaved.

OpenRa.Game/Traits/AttackBase.cs

@@ -8,10 +8,12 @@ namespace OpenRa.Game.Traits
 {
 	class AttackBase : IIssueOrder, IResolveOrder, ITick
 	{
-		public Actor target;
+		[Sync] public Actor target;
 
 		// time (in frames) until each weapon can fire again.
+		[Sync]
 		protected int primaryFireDelay = 0;
+		[Sync]
 		protected int secondaryFireDelay = 0;
 
 		int primaryBurst;