Merge pull request #1308 from tschneidereit/nat

Add rough but working unit testing script for the SpiderMonkey shell
Avoid using closures in Object and Number as to speed up startup time.
Coerce as string before resolving names.
Merge branch 'nat' of https://github.com/mozilla/shumway into nat
Implement mouseX/Y.
Make sure the Mouse class is initialized before using it.
Use seperate flags for invalid bounds and rect.
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?