Log Message:
Update to 1.19.  Closes PR pkg/22711 by Lloyd Parkes.  Changes since 1.17:

  1.19 - Messed up applying some of the patches in 1.18 :-(
  1.18 - Added support for specifying unsigned integer values [0; 2^32-1]
         Thanks to Richard Gerrits for pointing out the problem.
         Added support for specifying Z/Y/Z for adiw, sbiw and movw.
         Thanks to Richard Barrington for suggesting this.
         Added support for a bunch of Mega devices.
         Thanks to Andreas Schwarz for supplying a patch with these.
         Fixed problems compiling with GCC 3.2
         Several people supplied patches, but I was just too busy
         integrating them.
         Thanks to Patrick Dreker for supplying the final patch.