Add libnetcdf, libhdf5, pydap and cfgrib to xarray.show_versions() (#2555)
Add libnetcdf, libhdf5, pydap and cfgrib to xarray.show_versions() (#2555)

* Add libnetcdf, libhdf5, pydap and cfgrib to xarray.show_versions()

* More fixup

* Show full Python version string

markelg/xray,jhamman/xarray,pydata/xarray,shoyer/xarray,pydata/xarray,jhamman/xarray,jhamman/xarray,xray/xray,chunweiyuan/xarray,jhamman/xray,shoyer/xarray,pydata/xarray,shoyer/xray,markelg/xray,markelg/xray