Files
-----
    scs_mpi_internal.c
	Contains wrappers for the MPI calls the simulator uses internally. They are
	names _scs_MPI_*; e.g., _scs_MPI_Send
	DBG_MPI_INTERNAL can be used to show calls to these functions
	They call the corresponding PMPI_* functions directly.

    scs_mpi_wrappers.c
	Here are some support functions the MPI wrappers need plus the MPI
	function wrappers that are more complicated than just updating the
	local virtual time.

    scs_mpi_wrappersC.c
	The C language wrappers. Most of them change the communicator to the
	one the app uses. Some also send and wait for events.

    scs_mpi_wrappersF.c
	Same as above, but for Fortran.