For more information see:

• http://board.flashkit.com/board/showthread.php?t=541469
• http://math.stackexchange.com/questions/76457/check-if-a-point-is-within-an-ellipse

pointInEllipse(test, center, width, height) {
	dx = test.x - center.x
	dy = test.y - center.y
	return ( dx * dx ) / ( width * width ) + ( dy * dy ) / ( height * height ) <= 1
}