Fix to RSS feed link and paragraph on rsnapshot.

Hi Paul,

The RSS link wasn't showing up in the browser's address bar because the link had the wrong rel attribute ("alternative" instead of "alternate".) While I was there I added a link to the all comments feed from disqus.

(Don't know if you also want to add links in your sidebar HTML for those browsers such as chrome that don't show the feed box at all.)

Also added a paragraph on rsnapshot as you suggested.

Take it easy.

E.