- Pageviews per visitor. Extensions to use:
  .htm, .html, .asp, .php, .jsp, .xdl, .xhtml, .xml, .cgi, .pl, .shtml

- When the list of urls/referers/... are limited, a final
  entry "others" should sum all the non shown values.

- Countries by IP addresses? http://www.maxmind.com/app/geoip_country

- --before and --after, to limit the analysis to log
  entries matching the specified period.

- Processing time in seconds with decimal part, like 5,663 seconds.
  After this is implemented, it may print the lines for second speed
  if the time spent is more than 2 seconds or so.
  win32: http://mail.gnu.org/archive/html/bug-gnu-chess/2004-01/msg00020.html

- Page-specific referers

- An option to specify an external CSS name to link inside the HTML
  instead of the inline CSS.

- An option to specify the r/g/b values of the bidimentional maps

- Exclude google crawler accesses from weekday-hour map report?

- Modify parse_date() to cache the result.

- All the stats done by number of visitors and not by hits (optionally)

- Normal "Foobar by hits" statistics should show the percentage

- Better formatting for the new reports browser/os/domain in the
  plaintext report.
