Divided ActionScript into modules

This PR divides the ActionScript source file into separate module files for maintainability's sake.

However, this modularization (plus some new code included, too) _did_ result in the SWF's file size increasing from 2.496 KB to 3.304 KB, which is an increase of ~32%.  Not sure if that's too big of a size increase for the maintainability benefit. :confused:

Granted, it sure beats the heck out of the 270 KB SWF files that you get if you switch this over to be a Flex app instead of pure AS3.  :wink:

For comparison, the accompanying JavaScript file is ~17 KB minified, ~40 KB unminified.

Thoughts, @jonrohan?