Merge pull request #4 from unholyhen/master

Balloon: New art and balloon dragging.
Translating animations to TweenMax

Built-in animations does not take into account that the game pauses, so
we redo them as TweenMaxes instead.
Graphics tweaks
Cover has inputEnabled by default
Prettier menu
Better say function. Improved addSound

However, perhaps it would be more pretty if it was object-oriented?
Moved addSound to util file
Use set instead of setTo

Main reason: Less characters and more common function name.