Make the conformance section no-num.
Switch all the serializers over to html.tostring.
Switch to doc.iter() for some cases.
Make ToC generation more friendly to reruns.
Improve some error messages.
Properly omit boilerplate when it's already generated.
Fix a bug where content after a </pre> was dropped.
Add clearContents() and replaceContents(), and use them.
Rename data-biblio to data-biblio-type. Add data-autolink to specify type of autolink.
Add data-autolink='internal-ref', also process autolink elements with an href already, for better rerun behavior.
Fix linkTextVariations to actually produce more than one variation.