1. BUGFIX: In function makefile(), strip blanks from the nodename.
   This is necesary to match the behavior of parser.makeref() and
   parser.do_node().
2. BUGFIX fixed KeyError in end_ifset (well, I may have just made
   it go away, rather than fix it)
3. BUGFIX allow @menu and menu items inside @ifset or @ifclear
4. Support added for:
      @uref        URL reference
      @image       image file reference (see note below)
      @multitable  output an HTML table
      @vtable
5. Partial support for accents, to match MAKEINFO output
6. I added a new command-line option, '-H basename', to specify
   HTML Help output. This will cause three files to be created
   in the current directory:
      `basename`.hhp  HTML Help Workshop project file
      `basename`.hhc  Contents file for the project
      `basename`.hhk  Index file for the project
   When fed into HTML Help Workshop, the resulting file will be
   named `basename`.chm.
7. A new class, HTMLHelp, to accomplish item 6.
8. Various calls to HTMLHelp functions.
A NOTE ON IMAGES: Just as 'outputdirectory' must exist before
running this program, all referenced images must already exist
in outputdirectory.

FLD: wrapped some long lines.