Bitwise identical refactoring of the code in DOME_initialize_sponges,
including renaming variables for greater clarity, adding variables for several
dimensional constants, and correcting comments.  This also includes more careful
handling of the DOME OBCs in DOME_set_OBC_data() to hopefully avoid some obvious
problems (noted in a comment about a "fight with T,S") that would arise if a
DOME case were set up that used temperature and salinity. Future revisions
should add more runtime parameters to specify the details of this case, but
properly doing so would involve changing the order of arithmetic; this has not
happened in this case.  All real variables in this module are now described in
comments.  All answers and output are bitwise identical.