fix bug in set type/ratio when operating on subsets

    ranmars->select_subset(nsubset,count,flag,work);

    // change types of selected atoms

    // flag vecftor from select_subset() is only for eligible atoms

    count = 0;

    for (i = 0; i < nlocal; i++)

      if (select[i] && flag[i]) {

    int eligible = 0;

    for (i = 0; i < nlocal; i++) {

      if (!select[i]) continue;

      if (flag[eligible]) {

        atom->type[i] = newtype;

        count++;

      }

      eligible++;

    }

    // clean up