Update createjs libraries to most recent version

Definitions update for easeljs v0.8, tweenjs v0.6, preloadjs v0.6 and soundjs v0.6.

There were many changes in this release, so I may have missed somethings. If someone else could give a look at this update as well, it would be nice.

Cheers!
I think `getItem(value?: string): Object;` is better. please see LoadQueue.getItem() method. http://www.createjs.com/Docs/PreloadJS/classes/LoadQueue.html