Make the new version of beginexp_xml live now that its been through
the paper effort for everyone. I've redirected everything to beginexp_html.php3 (the front end to the XML version), including the plab and bui pages. I've stuck a redirect in the old beginexp.php3, to make it easy to bring back the old version in case something goes wrong. Just comment out the lines at the top and reinstall, along with changing the other links to it.