v1.0.2: added a missing sync check in music to prevent crashes

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

@@ -129,32 +129,34 @@ 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) {
-			if (trackList == null || trackList.length == 0 || player.isLooping() || music != player){
-				return;
-			}
-
 			//we do this in a separate thread to avoid graphics hitching while the music is prepared
 			//FIXME this fixes graphics stutter but there's still some audio stutter, perhaps keep more than 1 player alive?
 			new Thread(){
 				@Override
 				public void run() {
+					synchronized (Music.INSTANCE) {
+						if (trackList == null || trackList.length == 0 || player.isLooping() || music != player){
+							return;
+						}
+
 						Music.this.stop();
 
-					if (trackQueue.isEmpty()){
+						if (trackQueue.isEmpty()) {
-						for (int i = 0; i < trackList.length; i++){
+							for (int i = 0; i < trackList.length; i++) {
-							if (Random.Float() < trackChances[i]){
+								if (Random.Float() < trackChances[i]) {
 									trackQueue.add(trackList[i]);
 								}
 							}
 							if (shuffle) Collections.shuffle(trackQueue);
 						}
 
-					if (!enabled || trackQueue.isEmpty()){
+						if (!enabled || trackQueue.isEmpty()) {
 							return;
 						}
 
 						play(trackQueue.remove(0), trackLooper);
 					}
+				}
 			}.start();
 		}
 	};