[STABLE] HUGE Update

Additions:
- Mushroom Item Block
- Mushroom Physics
- UI Tweening
- Fledged out Level Select interface
- Clouds (Paralaxable)

Changes:
- Better Menu Consistency
- Many bugs fixed
- Etc etc etc!

This update adds a lot more "active" content to be seen on screen in all
game states, including the level select menu which now looks better by
having a backdrop to the levels to pick from and having clouds floating
and various speeds in the background. A lot of replay code has been
rewritten a little bit and few tweaks are spread about. Also mushrooms
are now attainable and work just as they should!