Added aac to the AudioResolver

MediaBrowser.Controller/Resolvers/AudioResolver.cs

@@ -36,6 +36,7 @@ namespace MediaBrowser.Controller.Resolvers
             {
                 case ".mp3":
                 case ".wma":
+                case ".aac":
                 case ".acc":
                 case ".flac":
                 case ".m4a":

MediaBrowser.Model/DTO/AudioOutputFormats.cs

@@ -3,6 +3,7 @@ namespace MediaBrowser.Model.DTO
 {
     /// <summary>
     /// These are the audio output formats that the api is cabaple of streaming
+    /// This does not limit the inputs, only the outputs.
     /// </summary>
     public enum AudioOutputFormats
     {