image2palette: Simple K-means color clustering

Clustering pixel colors of image (K-means) in L/a/b color space to make palette.

image2palette() parses image into pixels in L/a/b space, and returns major color components clustered by k-means method. It also returns the name of colors and palette.

--- Usage example

%% (1) Version 1. Pre-defined image
nCluster = 4;
imagefullpath = [pwd, '\' 'football.jpg'];
image2palette( nCluster, imagefullpath );

%% (2) Version 2. Select image using GUI handle
nCluster = 4;
image2palette( nCluster )

Color label reference: https://en.wikipedia.org/wiki/Web_colors