[feat] CIE-LAB Color Model

[logaretm]

CIE-LAB color model should be implemented. With basic conversions from and to RGB.

The CIELAB color space (also known as CIE Lab* or sometimes abbreviated as simply "Lab" color space) is a color space defined by the International Commission on Illumination (CIE) in 1976. It expresses color as three numerical values, L* for the lightness and a* and b* for the green–red and blue–yellow color components. CIELAB was designed to be perceptually uniform with respect to human color vision, meaning that the same amount of numerical change in these values corresponds to about the same amount of visually perceived change.

This is not a supported CSS format, so I guess its format should follow the others by convention, otherwise, if there is an established convention to represent a CIE-LAB value it should be used as its parse and format targets.