added missing value support for cosmo GRIB files

src/cdi_util.c

src/stream_cdf.c

src/stream_cgribex.c

src/stream_cgribex.h

src/stream_grb.c

src/stream_gribapi.c

src/stream_gribapi.h

src/varscan.c

src/varscan.h

src/vlist_var.c