Add GPL modules

MediaBrowser.Model/Services/IHasRequestFilter.cs

@@ -0,0 +1,21 @@
+
+namespace MediaBrowser.Model.Services
+{
+    public interface IHasRequestFilter
+    {
+        /// <summary>
+        /// Order in which Request Filters are executed. 
+        /// &lt;0 Executed before global request filters
+        /// &gt;0 Executed after global request filters
+        /// </summary>
+        int Priority { get; }
+
+        /// <summary>
+        /// The request filter is executed before the service.
+        /// </summary>
+        /// <param name="req">The http request wrapper</param>
+        /// <param name="res">The http response wrapper</param>
+        /// <param name="requestDto">The request DTO</param>
+        void RequestFilter(IRequest req, IResponse res, object requestDto);
+    }
+}