DECODR1312a

I finally got around to adding that NH4 tabulation file to DECODR. I could not figure out a way to do it independent of the "update sta.csvs" option. So DECODR1312a will generate a tabulation file of NH4 values 'offshore & 200m or greater' or negative that are datacoded 4 or zeroed. Run the nutrient data processing routine, select update sta.csvs and it will generate a 1311NH4DC4.csv in the Nut dir.
If the '0 -' (zero negative values) box is checked, it will tabulate those as well but they will be datacoded '0'.
Be aware that this file will not be overwritten if already present. It will be appended so if you want to regenerate a fresh version, you will have to manually delete the 1311NH4DC4.csv.