[relax-ng] RDDL for RELAX NG

Some time ago Mike did some work on creating an RDDL page for RELAX NG.
Since relaxng.org is now working again I would like to get this set up.

I took Mike's last version and diddled with it a bit (some of the roles
seemed wrong to me and I added a link to the OASIS web page) and put the
result at:

  http://www.thaiopensource.com/oasis/relax-ng-rddl.html

I have also uploaded a version of relaxng.rng with the agreed errata
applied:

  http://www.thaiopensource.com/oasis/relaxng.rng

I would suggest Norm install relaxng.rng as

  http://www.oasis-open.org/committees/relax-ng/relaxng.rng

and relax-ng-rddl.html as

  http://www.oasis-open.org/committees/relax-ng/ns/structure/1.0/

James