nco_xtr_cf_var_add() nco_is_spc_in_cf_att(): update WARNING messages about NC_STRING attributes not being CF-compliant

test parsing of BYTE/SHORT/INT/INT64 at mins

Remove call to nco_msh_lon_cf() for further debugging in 5.1.8 (it crashes Anaconda tests in a manner unreproducible on my laptop)

Implement nco_msh_lon_cf() in nco_rgr_wgt() to ensureCF-compliant longitude bounds in regridded files

Implement nco_msh_lon_cf() in nco_rgr_wgt() to ensureCF-compliant longitude bounds in regridded files

Implement nco_msh_lon_cf() in nco_rgr_wgt() to ensureCF-compliant longitude bounds in regridded files

implement nco_msh_lon_cf() which appears to work correctly when lon_ctr and lon_crn are consistent. However, some grids do not meet these criteria so do not rely on this routine just yet.