Server: add basic replay recording

Signed-off-by: Paul Chote <pchote@users.noreply.github.com>

OpenRA.Game/Network/ReplayRecorder.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using OpenRA.FileFormats;
@@ -85,6 +86,14 @@ namespace OpenRA.Network
 			writer.Write(data);
 		}
 
+		public void ReceiveFrame(int clientID, int frame, byte[] data)
+		{
+			var ms = new MemoryStream(4 + data.Length);
+			ms.WriteArray(BitConverter.GetBytes(frame));
+			ms.WriteArray(data);
+			Receive(clientID, ms.GetBuffer());
+		}
+
 		bool disposed;
 
 		public void Dispose()