This class stores the source coordinates of the entered stroke (in global pixel).
It contains the bounding box, start and end point, top-most point, right-most point, etc.
It can be retrieved from the recognizer and can be used to execute some actions depending on where the stroke was drawn.

	initialize-release
	initializeStart:end:top:left:bottom:right:

	accessing	top
	bottom
	bottom:
	bottomLeft
	bottomRight
	end
	end:
	extent
	isOnBorder:
	isOnXBorder:
	isOnYBorder:
	left
	left:
	pointAt:
	right
	right:
	start
	start:
	top
	top:
	topLeft
	topRight

	initialize-release	top
	initializeStart:end:top:left:bottom:right:

	instance creation	top
	new Answer a new instance of the receiver (which is a class) with no indexable variables. Fail if the class is indexable.
	start:end:top:left:bottom:right: