Prevent mod code from changing Actor.Owner directly.

OpenRA.Game/Actor.cs

@@ -38,7 +38,7 @@ namespace OpenRA
 
 		public readonly uint ActorID;
 
-		public Player Owner { get; set; }
+		public Player Owner { get; internal set; }
 
 		public bool IsInWorld { get; internal set; }
 		public bool Disposed { get; private set; }

OpenRA.Game/World.cs

@@ -240,6 +240,11 @@ namespace OpenRA
 				rc.Metadata = new ReplayMetadata(gameInfo);
 		}
 
+		public void SetWorldOwner(Player p)
+		{
+			WorldActor.Owner = p;
+		}
+
 		public Actor CreateActor(string name, TypeDictionary initDict)
 		{
 			return CreateActor(true, name, initDict);