Function pbnify::quantize::build_palette

pub fn build_palette<I>(n: usize, pixels: I) -> Vec<Rgba<u8>> where
    I: IntoIterator<Item = Rgba<u8>>, 

Performs the median-cut algorithm, producing an n-color palette based on the given set of pixels.

If n is not a power of two, it will be rounded up to the smallest power of two greater than n.

If n is greater than or equal to the number of given pixels, then the input will be returned as the result.