Checking planner-rss autocategories

I’ve added `planner-rss-category-feeds’ to planner-rss. This examines
the text of the note and copies it to different RSS feeds depending on
the regular expression match. In the future, I might actually just run
a lot of hooks on the thing.

If this works, I should have a new entry in
http://sacha.free.net.ph/notebook/wiki/planner.rdf

../../notebook/emacs/emacs-wiki/planner-rss.el