PISM Storglaciaren example.

For the flowline case, start with that section of the User's Manual.  Then do:
  $ ./preprocess.sh
  $ ./psg_flowline.sh N   # N processors

For the PRELIMINARY 3d case, which is not yet documented in the User's Manual, do:
  $ ./preprocess.sh
  $ ./sg_create_3d.py
  $ ./psg_3d.sh N         # N processors

