Changes by: Jason Hickey (jyh at cs.caltech.edu)
Date: 2006-12-05 19:41:00 -0800 (Tue, 05 Dec 2006)
Revision: 9820
Log message:

      Some delayed additions.
      
      Array efficiency:
         It used to be that code like this was quadratic because
         the arrays were flattened during the +=.  Do not do it.
      
         foreach(x, $a)
             y[] += $x
             export
      
      Added a random() function.
      
      Added {decode,encode}-uri functions.