I added the following code to ss2gg which has been named ss2grb

   1) grib2 output (requires wgrib2 to be on the path)
   2) interpolation to mb (log pressure interpolation)

   ss2grb will compile with both gnu gfortran and intel ifort
   ss2ll.pl is a perl script to convert to lat-lon grids
   makefile.gnu - makefile for ss2grb
