* New APIs: fadeMasterTo, fadeMasterFrom, set masterVolume, instance.endFade, tween.end
* Added "Master" volume control
* Improved looping implementation (loop on SoundComplete rather than 9999)
* Optimized calling addSound() with an already mapped type
* Fixed bug with SoundComplete event
* Optimized ENTER_FRAME listener to only run while Tweens are active
* Optimized tweens to reduce getTimer() calls
* Other small API fixes