Improve Performance

[luanpotter]

As per discussed here, there is a performance impact when playing sounds at a really fast rate (like 2 per second). We need to take a look at what's causing this.

[luanpotter]

This was fixed on 0.7.0. Now you can change the releaseMode to STOP in order for it to not be release. Then you can load the asset once with setUrl and then use resume to play as needed (this fixes @matejthetree problem with performance on the first sound played on flame), using something like this:

    // setup
    AudioPlayer player = new AudioPlayer();
    player.setReleaseMode(ReleaseMode.STOP); // this will not release the player when finished
    player.setUrl('...url...'); // this will prepare the player and leave it ready

    // play
    player.resume(); // instantly plays the sound

    // dispose (after game/stage finishes)
    player.release();