Fixed an issue where first track is skipped after playback completes.

Calling next() and then playback.start() results in two attempts to load a file. The first fails due to the player not being prepared, which then causes onError() to be invoked, which tells the app to skip to the next track.

Resolves timusus#415

Author: timusus

app/src/main/java/com/simplecity/amp_library/playback/PlaybackManager.java

@@ -514,8 +514,9 @@ public void play() {
             long duration = playback.getDuration();
             if (queueManager.repeatMode != QueueManager.RepeatMode.ONE && duration > 2000 && playback.getPosition() >= duration - 2000) {
                 next(true);
+            } else {
+                playback.start();
             }
-            playback.start();
 
             musicServiceCallbacks.cancelShutdown();
             musicServiceCallbacks.updateNotification();