make HTML5 DOM trees less insane

 HTML::HTML5::Sanity is a Perl library tidying HTML::HTML5::Parser.
 .
 The Document Object Model (DOM) generated by HTML::HTML5::Parser meets
 the requirements of the HTML5 spec, but will probably catch a lot of
 people by surprise.
 .
 The main oddity is that elements and attributes which appear to be
 namespaced are not really. For example, the following element:
 .
  <div xml:lang="fr">...</div>
 .
 Looks like it should be parsed so that it has an attribute "lang" in
 the XML namespace. Not so. It will really be parsed as having the
 attribute "xml:lang" in the null namespace.