Gravatar support

I’ve added gravatar support to the website. The gravatar system is a clever way to create identity on-line: e-mails are associated with images. Critically, the URL associated with an e-mail doesn’t include the e-mail itself, but instead an MD5 hash — this way, spammers can’t harvest your address.

I was disappointed to discover that Google Chat doesn’t have support for gravatars — a Google labs feature I would use.