Add GPL modules

MediaBrowser.Controller/Entities/IMetadataContainer.cs

@@ -0,0 +1,19 @@
+using MediaBrowser.Controller.Providers;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Controller.Entities
+{
+    public interface IMetadataContainer
+    {
+        /// <summary>
+        /// Refreshes all metadata.
+        /// </summary>
+        /// <param name="refreshOptions">The refresh options.</param>
+        /// <param name="progress">The progress.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        Task RefreshAllMetadata(MetadataRefreshOptions refreshOptions, IProgress<double> progress, CancellationToken cancellationToken);
+    }
+}