- Set default debug_model_step=0 (was 99999999)
- Add debug_model_[i,j,iblk,task] to define the debug_model diagnostic point
  in local grid index space.  If this point is not set and debug_model
  is turned on, it will use lonpnt(1),latpnt(1).
- Rename forcing_diag namelist/variable to debug_forcing to be more
  consistent with other "debug_" namelist variables
- Rename the local variable forcing_debug in ice_forcing.F90 to local_debug
  to avoid confusion with global varaible debug_forcing.
- Add namelist variable optics_file.  Was hardwired in ice_forcing_bgc.F90
- Update optics file variable name to read, still hardwired in model.
- Update setting of nbtrcr_sw and allocation of trcrn_sw.   nbtrcr_sw
  was not set in icepack after it was computed and trcrn_sw was allocated
  before nbtrcr_sw was computed.  This impacts the dedd_algae implementation
  which still isn't working.
- move default distribution_wgt_file for gx1 to set_nml.gx1
- update test suite, add testing of debug_model_[i,j,iblk,task], add addtional
  testing of maskhalo
- update documentation

- update ice_broadcast to sync up serial and mpi versions
- add get_rank to ice_communicate.F90
- add global_[min/max]val_scalar_int_nodist method to ice_global_reductions.F90
- add tripole output in ice_blocks.F90 with debug_blocks
- update set_nml.tx1 to set ns_boundary_type to 'tripole', was 'open'

- add grid_type and ns_boundary_type tripole check
- update sumchk unit test to check both Nface and center points.  these are treated
  differently for tripole grids.
- update documentation of unit tests