fadeOut(color, duration = 1000, onComplete) {
		this._fadeOut.color = colorPool.get(color);
		this._fadeOut.tween = tweenPool
			.get(this._fadeOut.color)
			.to({ alpha: 0.0 }, { duration })
			.onComplete(onComplete || null);
		this._fadeOut.tween.isPersistent = true;
		this._fadeOut.tween.start();
	}
fadeOut(flash) effect<p>
screen is filled with the specified color and slowly goes back to normal
@param {Color|string} color - a CSS color value
@param {number} [duration=1000] - expressed in milliseconds
@param {Function} [onComplete] - callback once effect is over
@example
// fade the camera to white upon dying, reload the level, and then fade out back
me.game.viewport.fadeIn("#fff", 150, function() {
    me.audio.play("die", false);
    me.level.reload();
    me.game.viewport.fadeOut("#fff", 150);
});