Log Message:
Update from 2.20 to 2.22.

   Release 2.22.

   Added clone method.
   Contributed by Holger Smolinski <holger@kunterbunt.bb.bawue.de>

   Release 2.21

   Minor tweaks sync up with bleadperl:
     - VMS optimizer tweaks to the Makefile.PL
     - MacOS support
     - Added alignment test

   Added example to the MD5 POD that shows how to calculate the
   digest of Unicode strings.