added protocol versioning. AssignPlayer order is dead.

OpenRa.FileFormats/ProtocolVersion.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.FileFormats
+{
+	public static class ProtocolVersion
+	{
+		// you *must* increment this whenever you make an incompatible protocol change
+		public static readonly int Version = 1;
+	}
+}