Setting song start time works on browser but not native

[JamsheedMistri]

In order to get around #95, I tried to make a native variable keeping track of time, then playing multiple songs at that time. It works on the simulator, but when I compile apps it plays from the beginning.

[yofreke]

example:

var audioManager = new AudioManager({ ... })
audioManager.play('mysong', {
  time: 2
});