Since Android 4.3 there is a hidden method that retrieve the audio hardware
latency: AudioSystem.getOutputLatency() (that should not be used according to
the android comments).

This latency should not be used when we use AudioTrack.getTimestamp since it
already take into account the hardware latency. So why adding a new method ?
Because AudioTrack.getTimestamp don't work with Bluetooth (it returns false).

This fix lip sync with Bluetooth audio.