- little rewriting to get closer to exf_bulk_largeyeager04.F - use ice/snow emissivity for downward longwave (as well as   upward lw). This results in significant changes in the output.
- little rewriting to get closer to exf_bulk_largeyeager04.F
- use ice/snow emissivity for downward longwave (as well as
  upward lw). This results in significant changes in the output.

altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h