* Add convert RGB to and from HSV with tests

* Add saturation func

* Add hue function

* Rename Saturation param

* Fix Hue and Saturation function mappings

* Add lightness func

* Add RGBToHSL func

* Add HSL to RGB

* Refactor variable names

* Fix saturation return value

* Add doc

* Add HSL tests

* Add doc

* Add saturation and hue tests

* Add hue and saturation to README