Update KSS website to be retina/mobile friendly

[JohnAlbin]

From #116, @kneath said:

Things I would be interested in: Updating the website to be retina & mobile-friendly. I hacked it out in an afternoon years ago and it shows.

The website is in the gh-pages branch of this Git repository. And is built with Jekyl.

PRs welcome!

[JohnAlbin]

Also, I've been using kss-node to generate docs for kss-node. Perhaps kss should eat its own dogfood?