Updates to Chemistry tables

[Behrooz-Roozitalab]

        * the html page was not created, it is fixed.
        * 4 digits are included for years, to use it for historical periods.
        * added "hm" as a case to enable using annual averaged files in addition to monthly files.
        * if config arg "trop_val" is pres500 : This version uses 500hPa as the tropopause threshold.
        * if config arg "trop_val" is tropopause (realistic case) : New method of defining troposphere, use  ozone (150ppb) or Trop_P. If not found, calculate total column
        * Added DMS to gases list - reported as DMS not S
        * Automatic addition of gaseous compounds even when not defined in the default list, 
        *   based on Carbon MW (12). It still needs ADF modification to read a list from yaml file. 

[justin-richling]

@Behrooz-Roozitalab Thanks again for continuing to revise this script. I left some comments for review. Please let me know if you have any questions or comments, you can reply to my comments if needed!

[Behrooz-Roozitalab]

@justin-richling Thanks for the comments. I resolved the edits I guess. Please check and let me know if something is missing!

[justin-richling]

@Behrooz-Roozitalab Looks good on my end, thanks again for the help!