Added additional audio properties

MediaBrowser.Model/Entities/Audio.cs

@@ -3,5 +3,8 @@ namespace MediaBrowser.Model.Entities
 {
     public class Audio : BaseItem
     {
+        public int BitRate { get; set; }
+        public int Channels { get; set; }
+        public int SampleRate { get; set; }
     }
 }