Function dither_func_stucki

pub fn dither_func_stucki(data: &mut [u8], width: usize) -> Result<()>

Stucki’s method

Transform coefficients
			curr	8/48	4/48
	2/48	4/48	8/48	4/48	2/48
	1/48	2/48	4/48	2/48	1/48