add_MARBL: write MARBL log to CESM log files every time step

[mnlevy1981]

In POP, we call print_marbl_log() after every call to surface_flux_compute() and interior_tendency_compute(); for some reason, with #9 and #28 I decided to only call the function if MARBL aborted. Printing it after every surface flux / interior tendency call will keep messages in the log file organized temporally -- if there are warnings from the CO2 solver, we currently see them at the end of cesm.log instead of mixed in with other log messages from the model day in which they were generated.

[mnlevy1981]

This was fixed in b51c5a9 but I didn't close the issue ticket at that time