Feature images

Further experiments in the static code generator. I've now added a feature image setting to the YAML file that generates each post. It appears in links via the og:, twitter: and itemprop metadata tags when syndicating content, and behind the date in the list view. Thanks to a post on Alis's page pointing out a WordPress plugin that generates page screenshots, and it's freely available link, my site can now default to a page-snippet image if there's no feature image added for a post.

I like it. Adds something to the site having images give more of a sneak peak on what a post is saying. Thoughts?

Incidentally, I also discovered that gimp has a "capture webpage" option for creating an image. That's neat.