+Created remapping_attic.F90

  Created the new module remapping_attic to hold older versions of remapping
code that are no longer used by MOM6.  The subroutines is PosSumErrSignificant,
remapByProjection, remapByDeltaZ and integrateReconOnInterval were moved to
remapping_attic, where they can be tested by calling remapping_attic_unit_tests.
The hard-coded old_algorithm logical module variable and the code it wraps were
also eliminated.  Also added a schematic description of the units of the real
variables in the various routines in MOM_remapping and corrected some spelling
errors.  All answers are bitwise identical.