+(*)Write unscaled SIS2 restart files

[Hallberg-NOAA]

Revised the SIS2 code so that the output restart files are always exactly the same as they would be if no dimensional rescaling is applied. The input restart files can still have rescaling, so files written by previous versions of the code still work exactly as before. This does change the output, in the sense that the restart files are unscaled and some units documents in the restart files are corrected, but the solutions themselves are bitwise identical. Also, there are new (non-optional) unit scaling type arguments to several routines.

The specific changes in this commit include:

• Add a new optional conversion arguments to all of the register_restart_field routines in SIS_restart.F90.

• Add a new optional scale argument to all of the only_read_restart_field routines in SIS_restart.F90.

• Added conversion factors to all register_restart_field() or register_restart_pair() calls for variables that are subject to dimensional rescaling.

• Revised the calculation of restart rescaling factors to reflect the rescaling that now occurs directly in the restore_state() call.

• Added new US arguments to SIS_C_dyn_register_restarts(), SIS_B_dyn_register_restarts(), SIS_dyn_trans_register_restarts(), ice_state_register_restarts(), ice_state_read_alt_restarts() and register_fast_to_slow_restarts()

• Corrected the rescaling of hin_max in ice_ridging().

• IG%H_to_kg_m2 is no longer being used anywhere, but rather than just eliminating it, it is being retained in the code to maintain compatibility with older restart files.

• Removed the unused H_to_kg_m2 argument to rescale_ice_state_restart_fields()

[Hallberg-NOAA]

I have now done the requested rebase to dev/gfdl and force push to my branch.