Create common interface for SyncPlay requests

MediaBrowser.Controller/SyncPlay/ISyncPlayRequest.cs

@@ -0,0 +1,16 @@
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface ISyncPlayRequest.
+    /// </summary>
+    public interface ISyncPlayRequest
+    {
+        /// <summary>
+        /// Gets the request type.
+        /// </summary>
+        /// <returns>The request type.</returns>
+        RequestType Type { get; }
+    }
+}