added support for grib_api key stepType

ChangeLog

app/cdi.c

src/cdi.h

src/cdi.inc

src/cdiFortran.c

src/stream.c

src/stream_cdf.c

src/stream_cgribex.c

src/stream_ext.c

src/stream_gribapi.c

src/stream_ieg.c

src/stream_int.c

src/stream_int.h

src/stream_record.c

src/stream_srv.c

src/stream_var.c

src/taxis.h

src/varscan.c

src/vlist.c

src/vlist.h