Fixing clamr_checkall to stash a copy of the new_ncells in gpu_new_ncells
so that the load balance for the gpu does not use the updated value
Fixing the do_load_balance interface so that clamr_checkall works
and doesn't use an updated number of cells for the gpu_do_load_balance
call
Fixing the 1 write/3 read neighbor algorithm for the single CPU and
GPU code. The distributed code still needs to have these added.