Make RSS links more consistent

There were 2 RSS links on the sidebar, one linking to
http://foodfightshow.org/atom.xml and the other to
http://feeds.feedburner.com/TheFoodFightShow. I removed the less obvious
one next to the search box and made the more obvious one link to
/atom.xml, because that's the main site and is more helpful.

Widened the search box a touch to compensate for the RSS icon that's
gone now.
Merge pull request #2 from smith/tidy-up-rss-links

Make RSS links more consistent