Make the mouse wheel work in Flash on OS X

As I’m sure all you Mac users are painfully aware, the mouse wheel doesn’t work in Flash on Macs. Imagine my surprise, therefore, when testing out a new Flex-based bug tracking system, and finding that I was able to use my Mighty Mouse to scroll a List. The source of the page revealed a clue which eventually led to AS3.0 MouseWheel on Mac OS X. Seems to work pretty well, and should hold us over until we get this in the player.

(Note that the mouse wheel works as expected in AIR applications; this is for browser-based apps only.)