message: only add interunit bon entry if there are bonds
diff: @@ -139,8 +139,10 @@ function findPairLinks(unitA: Unit.Atomic, unitB: Unit.Atomic, params: LinkCompu
  }
  }
  + if (bondCount) {
  addMapEntry(map, unitA.id, new InterUnitBonds.UnitPairBonds(unitA, unitB, bondCount, state.bondedA.array, state.mapAB));
  addMapEntry(map, unitB.id, new InterUnitBonds.UnitPairBonds(unitB, unitA, bondCount, state.bondedB.array, state.mapBA));
  + }
  return bondCount;
  }
  