Optimize NumberUtilities.clamp

Math.max and .min are highly optimized by JS engines, so manually implementing them isn't useful.
Add frozen identity matrix to flash.geom.Matrix

To be used as default value for optional Matrix-typed arguments.
Format cleanup in Graphics.ts
Implementation, documentation and tests for basic Graphics methods

The AS3-facing side of things, i.e. the recording, not the playback on a canvas.

Implemented methods:
 - moveTo
 - lineTo
 - beginFill
 - lineStyle
Add structural equality test to unit.js
Implementation of very basic bounds calculation for Graphics

moveTo and lineTo now extend the bounds rectangles roughly in the right way.
Change Graphics path commands from static consts to an enum

Much, much nicer to handle.
Introduce GFX.ColorUtilities.rgbaToCSSStyle

Useful for deserializing colors for drawing. Can and should get a cache.
Draw simple straight lines with solid fills and strokes

Yay?
Implement support for Graphics#curveTo

Also changed Graphics#clear to reset the instance's bounds.
Change all Graphics path command's coordinates to signed ints

People might want to use negative coordinates. Silly them.
Implement support for Graphics#cubicCurveTo
Address @mbebenita's and @tobytailor's review comments
Fix drawing of cubic curves
Fix drawing of cubic curves
Begin and close paths for Graphics fills and strokes
Fix Graphics unit test

Apropos of nothing, making the same stupid copy-and-paste mistake in both the production code and the unit test is truly annoying.
Store last coordinate in Graphics path commands

Needed to correctly calculate bounds for curves.
Introduce Geometry.quadraticBezierExtreme and use it to calculate bounds for Graphics#curveTo
Introduce Geometry.cubicBezierExtremes and use it to calculate bounds for Graphics#cubicCurveTo