The geolocation routines in wgrib2 are going to be changed.  The problems are 

   (1) internal routines are for a spherical earth
   (2) the IPOLATES library is for a spherical earth and the interface is
       grib1-centric.  Angles are only to milli-degrees.
   (3) many grids are unsupported.
   (4) staggering is unsupported.
   (5) non-spherical (i,j) -> (lat,lon) routines are slow

   (1) can been solved by using the gctpc or proj4 libraries. (done)
   (2) interpolation is to do
   (3) may be helped by proj4
   (4) staggering is to do
   (5) slow geolocation routines (use OpenMP, done), modify libraries (?)
