Methods to get what a point is in another matrix space.
Use cases: an element is transformed and you need to do another scale based around an arbitrary point in world coordinates.
The AS2 documentation for globalToLocal. http://help.adobe.com/en_US/AS2LCR/Flash_10.0/help.html?content=00001308.html
Should this go in Point.prototype or in DisplayObject.prototype? Point has less methods :) Flash has it on DisplayObject as well.
I guess I’ll put it there, too, to avoid circular module relationships.
Add `DisplayObject#globalToLocal` and `DisplayObject#localToGlobal`