reference to IRI-to-URI algorithm

The bibliographic reference to the Character Model
specification and/or the XLink specification, covering 
the algorithm for normalizing IRIs into URIs, should
(I believe) be updated to point to the IETF draft on IRIs.

The draft of 9 May 2004 is at
http://www.w3.org/International/iri-edit/draft-duerst-iri-07.txt

I note in passing that since IETF documents have explicit
expiration dates, something probably needs to be done
to accommodate the replacement of the draft of 9 May
with later drafts; otherwise, I believe that it will be
logically impossible for an implementation to conform to
our spec, since it will require that the implementation
conform to the draft of 9 May, and after 7 November 2004
it will be impossible to conform to the draft of 9
May since it will have expired.  I may be wrong.

-C. M. Sperberg-McQueen