changed the default Stage dimensions to 640-by-480; implemented 'scale' method on Fizz.Canvas wrapper class for returning scaled copies of a canvas; implemented Fizz.Graphic class for simpler graphics rendering; extended Fizz.Sprite class from Fizz.Graphic class and moved non-animation-specific code into Fizz.Graphic; implemented Fizz.Fontsheet for storing and retrieving sets of typographic glyphs; implemented Fizz.Textbox class which acts as a dynamic DisplayGrid to render text; fixed recaching code for DisplayGroups which are configured to be cached; wrote unit tests for Fizz.Graphic, Fizz.Fontsheet, and Fizz.Textbox; divided large test suites into smaller test suites;