Common Lisp bindings to the popular [Gravatar](https://secure.gravatar.com/) service.
### (image-url _email_ &key _size default force-default-p rating_)
* _size_ is an integer for the number of pixels along a side. Gravatar images are always square.
* _default_ may be either a URL to your own image, or one of `:404`, `:mm`, `:identicon`, `:monsterid`, `:wavatar`, or `:retro`.
* _force-default-p_ indicates whether to always use the default, even if another image is available. This is useful when you use a hash-based default like `:identicon` that is unique per user.
* _rating_ may be one of `:g`, `:pg`, `:r`, or `:x` and indicates the level of "vulgarity" that you allow on your site. The default is `:g`.
### (profile _email_)
This returns the cl-json formatted profile of the user. Eventually we'll parse this into better structures, but that is TBD.
### (profile-url _email_ _js-callback_)
### (qr-code-url _email_ &key _size_)
This returns an image URL for a QR code that encodes the URL of the user's profile page.