The cgi script currently only needs read-only access to the database.

With this change, the cgi script uses another mysql default file which
is assuemed to contain read-only credentials and can be provided public
readable. This enables the webserver to run without special privileges.

Module CGI already exports a menu sub. Avoid redefinition warning in
server log.

By default the groups page shows finished groups for the last
seven days. This patch allows the number of days be
overridden by a query parameter "days"

This feature was first implemented by Peter in his working copy,
but his implementation is different, that it limits the time range
for active groups as well.

If the group table is constrained by username, show that in the header
line.

Donald: Took this from Peter although I'm not sure what these values
really mean.

Make html a little bit cleaner.

shorten header width and use himan readble units.

Leave maxtime empty if server has no limit

Shorten header, use human readble units

We already show that information from the encapsulating context.

We want more space between the selector and the table

To prepare for further changes.

Instead of serif courier fonts use monospace. Make tables contents more readable.

Avoid killing the browser

We can select the pages via a header line now, so there is no need to
have a separate selection page. Start with groups page right away.