Initial revision
Add improvements by Fabrizio Fioravanti <fioravan@dsi.unifi.it>,
<fioravanti@computer.org> http://ww.dsi.unifi.it/~fioravan:
alphabetical index for fast access and "Contributor index" instead of
"Author index"
Pick up optional e-mail and URL fields in author entries.  Print them
as HREF="mailto:" (e-mail) or plain HREF (URL) entries.
Add code to print "progress" indication conditioned on a flag.
Format and print multiple authors in a comma-separated list.
Add code to translate some numbers (2, 3, and 4) into words for
indexing.  Add code to make sure index entries aren't dropped in case
of duplicates.  Put parentheses around authors to match Fabrizio's
code.
Check that cross references (href="#...") go somewhere.
Print entries without area or without type.
Change the main entry writing loop to be driven by the entries, not by
letters.  We don't have to change @sortedentries and don't have to
keep checking in case it is empty.
Don't print NO AREA and NO TYPE if everything has an area and a type.
Print periods (.) while reading terms rather than all the names.
Count and print the number of entries.
Get the time string from localtime in a scalar context instead of an
array context and formatting it ourselves.
Create a subroutine to rename the existing page to be a backup, and
rename the new page to be the existing page.
Add conversions to index more numbers as names.
Write the date and time of processing to the page.
Write area and type indices to a separate page to keep the main page short(er).
End and "See also" with a period.
Add entries for references to implementations and further links.
Entries without definitions now have links back to "need help" --
hopefully it may attract some people.  Change cross references to use
<=> ...> rather than <...>.  The former is used in two other entries.
I realize with more contributors, the simpler the syntax, the better.
Add a section in the index page to point out definitions with
implementation links.
Change to put each definition in its own file.  A single file was
growing too large to download (and most indexers put it toward the
bottom because it is so big).  Split the indices into a page of terms
with definitions, an index by area, and an index by type.  Add a new
type: para(llel).  Improve cross references so terms can have HTML
markup in them, e.g., <=> R<sup>+</sup>-tree>.
Parse HTML tags which use ='s correctly.  Add more space and stars
before the Unknown HREF message to make it more visible.
Add a cryptograph and compression area.
There may be multiple authors, so split entry before checking validity.
Add links to areas and types page so you can see all the areas or
types and so you can jump there easily.
Add note that this software is in the public domain
Copy the modified date from the entry to the HTML page.  Elaborate the
"no definition, yet" message: add a link to send me mail to ask for a
definition.  Get the time of writing the HTML once rather than two
different times for the HTML entry intro and concl -- this avoids
possible time inconsistencies.