internal package Foswiki::Plugins::WysiwygPlugin::TML2HTML 
Convertor class for translating TML (Topic Meta Language) into
HTML
The convertor does 
not use the Foswiki rendering, as that is a
lossy conversion, and would make symmetric translation back to TML
an impossibility.
The design goal was to support round-trip conversion from well-formed
TML to XHTML1.0 and back to identical TML. Notes that some deprecated
TML syntax is not supported.
  ClassMethod new() 
Construct a new TML to HTML convertor.
  ObjectMethod convert( $tml, \%options ) → $tml 
Convert a block of TML text into HTML.
Options: 
-  \&expandVarsInURL is a reference to a static function:
     expandVarsInURL($url, \%options) -> $url
     that expands selected variables in URLs so that, for example,     
 tags appear as pictures in the wysiwyg editor.
  -  \&isKnownColour - pointer to a function that will determine if the     parameter maps to a known HTML colour e.g. BLACK -> black and return     the colour name if it does, or undef otherwise.
  -  \%xmltag is a reference to a hash. The keys are names of XML-like     tags. The values are references to a function to determine if the     content of the tag must be protected:
     fn($markup) -> $bool
     The $markup appears between the  delimiters.     The functions may modify the markup.
  -  dieonerror makes convert throw an exception if a conversion fails.     The default behaviour is to encode the whole topic as verbatim text.
  -  \@keeptags - gives an array of HTML tag names that are to have     the TMLhtml class added, to protect them during subsequent     HTML2TML conversion.
  -  \@keepblocks - gives an array of (lowercase) tag names of HTML block tags      that are to be protected. Default is [ 'script', 'style' ]
  -  forcenoautolink can be set to a true value to apply NOAUTOLINK     across the entire conversion.