Implementing YADIS with no new software

[Martin Atkins]

With a few changes to the discovery mechanism, I believe that it would
be possible to support all this YADIS business with no further
implementation.

There are two key changes:
* The <link> element in the retrieved HTML document, rather than being
required to point at an identity server, is instead specified as
pointing at a capability document. This doesn't really change much
except the terminology used.
* The capability declaration document (the x-meta-identity thing) is
extended to support the specification of a URL to use as the endpoint
for each declared capability.

The following scenario then becomes possible:
* I install off-the-shelf OpenID server and LID server software onto my
server with no modifications.
* I create a STATIC FILE in my webroot which is an x-meta-identity
document noting that I support both LID and OpenID and that they can be
found at these other URLs, where my stock install server software can be
found.
* The HTML document at my identity URL LINKs to that static file as the
capability document.

Now I have an identity URL that supports both LID and OpenID without
having to use some fancy multi-protocol identity server or do any
programming.

Sound good?