added gradsdes ref data

.gitattributes

@@ -709,6 +709,8 @@ test/data/netcdf_testfile02.nc -text
 test/data/netcdf_testfile02_infon_ref -text
 test/data/netcdf_testfile02_sinfon_ref -text
 test/data/pl_data -text
+test/data/pl_data.ctl -text
+test/data/pl_data.gmp -text
 test/data/pl_data.grb -text
 test/data/select1_ref -text
 test/data/select2_ref -text

test/data/Makefile.am

@@ -11,5 +11,6 @@ REMAP_REF    = n16_bic_ref n16_bil_ref n16_con_ref n16_ycon_ref n16_laf_ref n16_
                n32_bic_ref n32_bil_ref n32_con_ref n32_ycon_ref n32_laf_ref n32_nn_ref n32_dis_ref
 SELECT_REF   = select1_ref select2_ref select3_ref select4_ref select5_ref
 DETREND_REF  = detrend_ref
+GRADSDES_REF = pl_data.ctl pl_data.ctl
 
-EXTRA_DIST = $(INPUTDATA) $(FILE_REF) $(GRIB_REF) $(NETCDF_REF) $(TIMSTAT_REF) $(SPECTRAL_REF) $(VERTINT_REF) $(REMAP_REF) $(SELECT_REF) $(DETREND_REF)
+EXTRA_DIST = $(INPUTDATA) $(FILE_REF) $(GRIB_REF) $(NETCDF_REF) $(TIMSTAT_REF) $(SPECTRAL_REF) $(VERTINT_REF) $(REMAP_REF) $(SELECT_REF) $(DETREND_REF) $(GRADSDES_REF)

test/data/pl_data.ctl

+* Generated by CDO version 1.6.6
+*
+DSET  ^pl_data.grb
+DTYPE  GRIB
+INDEX  ^pl_data.gmp
+XDEF 12 LINEAR -165.000000 30.000000
+YDEF 6 LINEAR -75.000000 30.000000
+ZDEF 4 LEVELS 900 90 9 0.9 
+TDEF 5 LINEAR 12:00Z02jan1978 1dy
+TITLE  pl_data.grb  12x6 grid
+UNDEF  -9e+33
+VARS  3
+t                  4  130,100  temperature  [K]
+lsp                0  152,1  log surface pressure
+geosp              0  129,1  surface geopotential (orography)  [m^2/s^2]
+ENDVARS