Give playback engine better control over the codec. Codec simply follows commands and doesn't concern itself with audio state. Get track change notification in on the actual last buffer insert of the track because now audio simply waits for a track change notify from PCM on the last track and it must be sent reliably. This is still at an intermediate stage but works. Codecs and plugins become incompatible.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29387 a1c6a512-1295-4272-9138-f99709370657
diff --git a/apps/pcmbuf.h b/apps/pcmbuf.h
index 992eb80..618b1ba 100644
--- a/apps/pcmbuf.h
+++ b/apps/pcmbuf.h
@@ -32,6 +32,7 @@
 void pcmbuf_play_start(void);
 void pcmbuf_play_stop(void);
 void pcmbuf_pause(bool pause);
+void pcmbuf_monitor_track_change(bool monitor);
 void pcmbuf_start_track_change(bool manual_skip);
 
 /* Crossfade */