rnd-20100309-2-src

* fixed potential crash bug caused by illegal array access in engine
  snapshot loading and saving code
* changed setting permissions of score files to be world-writable if
  the program is not installed and running setgid to allow the program
  to modify existing score files when run as a different user (which
  allows cheating, of course, as the score files are not protected
  against modification in this case)
* added (commented out) suggestions for RO_GAME_DIR and RW_GAME_DIR to
  the top level Makefile for Debian / Ubuntu installations
* added saving read-only levels from editor into personal level set
  (thanks to Bela Lubkin for the above four patches)