MpdResponse refactored (partial)

LibMpc/Message/MpdMessage.cs

@@ -0,0 +1,24 @@
+namespace LibMpc
+{
+    public interface IMpdMessage
+    {
+        IMpdRequest Request { get; }
+        IMpdResponse Response { get; }
+    }
+
+    public class MpdMessage : IMpdMessage
+    {
+        public MpdMessage(IMpcCommand command)
+        {
+            Request = new MpdRequest(command);
+        }
+
+        public void AddResponse(IMpdResponse response)
+        {
+            Response = response;
+        }
+
+        public IMpdRequest Request { get; }
+        public IMpdResponse Response { get; private set; }
+    }
+}