- Document fillmeldhtmlform method.

- Preserve xmlns="http://www.w3.org/1999/xhtml" On tags when it's
  provided in the parsed XML input during xhtml output (or figure out
  why it makes the XML writer go berserk and output every tag with
  that qualified namespace, or just output it by default in XHTML mode
  only if that makes sense).

- Revisit <![CDATA serialization.  Currently CDATA containers are
  thrown away at parse time, and are thus not present in the output
  stream.  Investigate how different browsers deal with this (esp. wrt
  to escaped cdata in "script" and "style" elements when XHTML
  serialization is used).

- Document the proper usage of <meta content="text/html;
  charset=ISO-8859-1" http-equiv="content-type">.  Maybe output an
  http-equiv content type tag by default matching the serlialization
  mode.

- Investigate why using the "plope.com" namespace identifier is bad.

- HTML serializer only calls _escape_cdata/_escape_attrib if necessary
  instead of calling it without regard to its need.  This needs to be done
  for the XML serializer too.