Proposal for "Services_Libravatar"

Libravatar.org is a web service similar to Gravatar that supports service federation and Gravatar fallback, as well as allowing users to link avatars images to openid accounts and use a stronger algorithm.

Services_Libravatar is a class that takes an email address or an openid URL, detects the type of account passed, checks the domain the account is on for the existence of a federated Libravatar instance (with Libravatar.org as fallback if none exists), and then composes a URL for the account's linked avatar image.

Source code can be found at: https://gitorious.org/services_libravatar
Bug tracker is at https://launchpad.net/services-libravatar