OpenMPI - hello, world

* Trivial example of MPI calls...
#include <stdio.h>
#include <mpi.h>

int main(int argc, char** argv) {
    // Initialize the MPI environment
    MPI_Init(&argc, &argv); // ...or just "MPI_Init(NULL, NULL);"

    // Get the number of processes
    int world_size;
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    // Get the rank of the process
    int world_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);

    // Get the name of the processor
    char processor_name[MPI_MAX_PROCESSOR_NAME];
    int name_len;
    MPI_Get_processor_name(processor_name, &name_len);

    // Print off a hello world message
    printf("Processor %s, rank %d of %d processors\n",
            processor_name, world_rank, world_size);

    for (int i = 0; i < argc; i++)
        printf("  %s/%02d: argv[%d] -->%s<--\n",
                processor_name, world_rank, i, argv[i]);

    // Finalize the MPI environment.

    return 0;