add support for GFAS fire flux and proper management of grids, depending on which dataset is used (CEDS or CARBON_TRACKER)

add DataCouplerCO2Box.py and associated namelist and namcouple, identical in functionality to DataCouplerAMIP.py

add support for co2 concentration and sending data from multiple variable to one oasis var (e.g. CO2-em-anthro and CO2-em-AIR-anthro)