Returns the length of a quaternion.
Original signature is 'float GLKQuaternionLength ( GLKQuaternion quaternion );'
Available in OS X x0.8 and later.
public static float Length (GLKQuaternion quaternion) { return (float)Math.Sqrt (quaternion.x * quaternion.x + quaternion.y * quaternion.y + quaternion.z * quaternion.z + quaternion.w * quaternion.w); }