several changes for co2box model in sources/data-coupler/ : various bugfixes and more logging ; rename oasisIn to oasisOut ; allow option to accumulate and add fields (e.g. emissions) or only read field for first timestep (e.g. initial co2) ; add constants and named scale factors (e.g. co2_ppm_to_mass) ; use global (not hemispheric) co2 box model

basic refactoring with new OasisOutVar (handling update and send internally) and renaming DataCouplerVar class to FileInputVar

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)