Add Gary to AUTHORS.

AUTHORS

@@ -4,6 +4,7 @@ John Carr <john.carr@unrouted.co.uk>
 Dave Borowitz <dborowitz@google.com>
 Chris Eberle <eberle1080@gmail.com>
 "milki" <milki@rescomp.berkeley.edu>
+Gary van der Merwe <garyvdm@gmail.com>
 
 Hervé Cauwelier <herve@itaapy.com> wrote the original tutorial.