Added N to play next song

src/audio/Audio.h

@@ -42,6 +42,7 @@ public:
     int getLoadedTrackCount() const; // get number of tracks loaded so far
     void shuffle();               // randomize order
     void start();                 // begin playback
+    void skipToNextTrack();       // advance to the next music track
     void toggleMute();
     void setMuted(bool m);
     bool isMuted() const { return muted; }