rendering a calendar less expensive.
* Added a function displayCalendar($theme, $active_date) to functions.inc.
* Adjusted index.php so it would support URIs formated like
  "?date=$unix_timestamp".
* Integrated the calendar in my personal theme: themes/Dries/theme.class.
  If you want to include the calendar in your theme, check the code in my
  $theme->footer(): global $date and call displayCalendar($theme, $date).

Check the main page at http://beta.drop.org/ with theme 'Dries' to see it
yourself!