Redesign DookLiberation control flow.

FileLiberator/IAudioDecodable.cs

@@ -0,0 +1,17 @@
+using Dinah.Core.Net.Http;
+using System;
+
+namespace FileLiberator
+{
+    public interface IAudioDecodable : IStreamProcessable
+    {
+
+        event EventHandler<Action<byte[]>> RequestCoverArt;
+        event EventHandler<string> TitleDiscovered;
+        event EventHandler<string> AuthorsDiscovered;
+        event EventHandler<string> NarratorsDiscovered;
+        event EventHandler<byte[]> CoverImageFilepathDiscovered;
+
+        void Cancel();
+    }
+}