use MPI_COUNT to build M**LOC datatype
use MPI_COUNT to build M**LOC datatype

MPI_COUNT is the MPI datatype corresponding to MPI_Count.  i did not
realize that this was available until now.

jeffhammond/BigMPI,gentryx/BigMPI,gentryx/BigMPI,jeffhammond/BigMPI,jeffhammond/BigMPI,gentryx/BigMPI