Convert html br to xhtml and use strong instead of b

This is a minor patch to tidy up some of the hard coded html.
This converts several instances of br tag from the html form to the xhtml form br /. Drupal uses an xhtml doctype don't ya know ;)
This converts two uses of the presentational b tag to the semantically better strong tag - conforms to a strict xhtml doctype.

Patch created against the DRUPAL-5 tag, using 'svk diff' in my local development setup (so no -f for function names), but since it's just an html tidy up I hope that doesn't matter.