Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004 Stéphane Carrez, France Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved.