playbin: use gconfaudiosink

src/playbin.vala

@@ -44,6 +44,12 @@ class Playbin : Object {
     }
 
     construct {
+        // gstreamer docs: GNOME-based applications, for example, will usually
+        // want to create gconfaudiosink and gconfvideosink elements and make
+        // playbin3 use those, so that output happens to whatever the user has
+        // configured in the GNOME Multimedia System Selector configuration dialog.
+        this.playbin.audio_sink = Gst.ElementFactory.make ("gconfaudiosink", null);
+
         this.playbin.source_setup.connect (this.source_setup);
         this.playbin.about_to_finish.connect (this.about_to_finish);