output netcdf, use CF Conventions

[rgcoe]

• Closes Use CF conventions #2
• Closes output netCDF #1
• Integrate into existing tool?

[rgcoe]

@tcj - I've included the critical functionality in this, but it'd probably be best to better integrate sd_csv_to_netcdf into sd_file_parser.py, for example by setting the outputFileType argument when calling sd_file_parser.main, which if you set outputFileType='.nc' it will run a method that includes all the content in sd_csv_to_netcdf (and maybe just make the CSVs in temporary directories?).