add half a bond length safety margin to bond length based cutoff estimates

  // cutneighghost = pair cutghost if it requests it, else same as cutneigh

  // also consider bonded interactions for estimating the the neighborlist

  // and communication cutoff. we use the bond equilibrium distance as

  // cutoff, if only a bond style exists. if also an angle style exists we

  // multiply by 2, for dihedral or improper we multiply by 3.

  // and communication cutoff. we use the 1.5x the bond equilibrium distance

  // as cutoff, if only a bond style exists. if also an angle style exists we

  // multiply by 2.5, for dihedral or improper we multiply by 3.5. (1,2, or 3

  // bonds plus half a bond length total stretch).

  // this plus "skin" will become the default communication cutoff, if no

  // pair style is defined. otherwise the maximum of the largest pairwise

  // cutoff of this is used.

       maxbondcutoff = MAX(bondcutoff,maxbondcutoff);

    }

    if (force->dihedral || force->improper) {

      maxbondcutoff *= 3.0;

      maxbondcutoff *= 3.5;

    } else if (force->angle) {

      maxbondcutoff *=2.0;

      maxbondcutoff *=2.5;

    } else {

      maxbondcutoff *=1.5;

    }

  }