Add vtables for ERA-interim files.
Update g1print for ECMWF table128
Update rd_grib1 for ECMWF earth radius. It's unclear what they
actually use, so code it to the standard.
Update rrpr so RH is computed on model levels only if we have all the
required variables. Allow SEAICE to be a fraction or flag. Calculate
SNOWH in rrpr when we have model-dependent information. SNOWH must
be in the Vtable for this to occur, otherwise, real.exe's default
behavior is used (correct only for NAM).
git-svn-id: https://svn-wrf-wps.cgd.ucar.edu/trunk@583 86b71a92-4018-0410-97f8-d555beccfc3a