v2.3.0: fixed track looping interfering with fade behaviour

SPD-classes/src/main/java/com/watabou/noosa/audio/Music.java

@@ -162,6 +162,8 @@ public enum Music {
 	private com.badlogic.gdx.audio.Music.OnCompletionListener trackLooper = new com.badlogic.gdx.audio.Music.OnCompletionListener() {
 		@Override
 		public void onCompletion(com.badlogic.gdx.audio.Music music) {
+			//don't play the next track if we're currently in the middle of a fade
+			if (fadeTotal == -1f) {
 				//we do this in a separate thread to avoid graphics hitching while the music is prepared
 				if (!DeviceCompat.isDesktop()) {
 					new Thread() {
@@ -175,6 +177,7 @@ public enum Music {
 					playNextTrack(music);
 				}
 			}
+		}
 	};
 
 	private synchronized void playNextTrack(com.badlogic.gdx.audio.Music music){