Bug: Angle calculation wrong

[nthState-Chris]

Should be:

func angle(between finishPoint: CGPoint) -> CGFloat {
    let center = CGPoint(x: finishPoint.x - self.x, y: finishPoint.y - self.y)
    let radians = atan2(center.y, center.x)
    let degrees = radians * 180 / .pi
    return degrees >= 0 ? degrees : degrees + 360
}