avoid integer overflow and remove unused function argument causing it

    // stop at this point in bstr if imbalance factor < threshold

    // this is a true 3d test of particle count per processor

    double imbfactor = imbalance_splits(max);

    double imbfactor = imbalance_splits();

    if (imbfactor <= stopthresh) break;

  }

   calculate imbalance based on processor splits in 3 dims

   atoms must be in lamda coords (0-1) before called

   map particles to 3d grid of procs

   return maxcost = max load per proc

   return imbalance factor = max load per proc / ave load per proc

------------------------------------------------------------------------- */

double Balance::imbalance_splits(int &maxcost)

double Balance::imbalance_splits()

{

  double *xsplit = comm->xsplit;

  double *ysplit = comm->ysplit;

  MPI_Allreduce(proccost,allproccost,nprocs,MPI_DOUBLE,MPI_SUM,world);

  maxcost = 0.0;

  double maxcost = 0.0;

  double totalcost = 0.0;

  for (int i = 0; i < nprocs; i++) {

    maxcost = MAX(maxcost,allproccost[i]);

  FILE *fp;                  // balance output file

  int firststep;

  double imbalance_splits(int &);

  double imbalance_splits();

  void shift_setup_static(char *);

  void tally(int, int, double *);

  int adjust(int, double *);