This class implements the controls for manipulating the viewpoint of a camera using the mouse.

Currently clicking and dragging on the bitmap moves the camera forward/back and turns it left/right.

Shift-clicking and dragging moves the camera left/right and up/down.

Control-clicking and dragging turns the camera left/right.

Shift-Control-clicking and dragging turns the camera up/down.

	camera control
	moveCamera:

	event handling
	handlesMouseDown: mouseDown: mouseUp:

	initialization
	initializeWith:

	properties
	getMoveScale getRotationScale setMoveScale: setRotationScale:

	accessing	top
	extent: Do nothing; my extent is determined by my image Form.
	getCenter
	setCenter:

	camera control	top
	moveCamera: Move the camera an amount and direction determined by the current position of the mouse and which modifier keys are held down.

	event handling	top
	handlesMouseDown: Do I want to receive mouseDown events (mouseDown:, mouseMove:, mouseUp:)?
	mouseDown: Handle a mouse down event.
	mouseUp: Handle a mouse up event.

	initialization	top
	initializeWith: Initialize this instance

	properties	top
	getMoveScale
	getRotationScale
	setMoveScale:
	setRotationScale:

	instance creation	top
	newFor: Initialize the camera controls and assign the camera they're controlling