several changes for co2box model in sources/data-coupler/ : various bugfixes...

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