Make RSS and Atom feeds for static websites.

The feed.Feed class takes a URL and grabs all the main.ul.li elements. Assuming they contain as, it gets the link and checks for content and metadata, like publishing time and description, and turns this into a feed. It exposes methods for producing feed.xml and feed.atom files.

The point is to be able to quickly generate (and regenerate) feeds without thinking about it.

For basic usage, see example.py.