Calculate the volo diagnostic in scaled units using the tmp_scale argument to
global_area_integral and undo this scaling with a conversion argument on its
register_scalar_field call.  Also corrected the units in the comments describing
the mass_celland masso variables in calculate_diagnostic_fields.  All answers
are bitwise identical.

  Renamed the internal variable tmpForSumming to masked_area in
compute_global_grid_integrals and corrected the description of its units from
[m2] to [L2 ~> m2].  All answers are bitwise identical.

  Corrected incorrect syntax in the descriptions of 4 positions variables in
write energy, 1 reused position variable in set_grid_metrics_from_mosaic and 1
position variable in bkgnd_mixing_CS.  Also added the unscaled units to the
comments documenting two lines of calculations in wave_speeds, and added the
scaled units to two variables related to the ice-shelf surface mass balance.
Only comments are changed and all answers are bitwise identical.

  Replaced the unused real tide_flow element of the file_OBC_CS type with the
logical OBC_file_used element to more clearly reflect that this placeholder
element is only here to avoid having a completely empty type.  The actual value
of this element is irrelevant, but some compilers require that all Fortran types
have at least one element.  This change eliminates a meaningless hard-coded real
variable with undefined units and a misleading name and replaces it with a
logical variable named to reflect its actual purpose.  All answers are bitwise
identical.