This formatter is used to serialize HTML content. The difference between
this formatter and the XMLFormatter is that while the XML formatter doesn't
have any semantic information about the document type being formatted,
this class handles tags like <br/> and transforms them to
HTML that non-XML-aware browsers can understand. Note that this creates
markap that is non-well-formed XML. If you want to be able to send HTML
code to old-browser but still create well-formed XML, use the XHTMLFormatter
instead.
