rainbow-mode had a big success and good feedbacks when I released it for the first time a couple of months ago.

Several users asked to me request its inclusion into Emacs. Therefore, some days ago, I proposed to merge it inside Emacs trunk. My request has been denied, but the mode has been added to the Emacs 24 package repository.

In the mean time, I've added support for hsl() and hsla() support, and added
CSS 3/SVG color names.