Dynamic Flash resizing

After my shockingly disappointing results (the size of the SWF increasing by more than 100x) while attempting to follow the plans laid out in Issue #354, I did a lot more reading and figured out how to make dynamic resizing of the Flash object work in pure AS3 _without_ switching to the Flex `UIComponent` class. The SWF size difference from prior to this commit is incredibly negligible.

Fixes #270.
Fixes #354.