message: Change looping in k3 term
  Fix smooth cutoff weighing by changing the loop in k3 term.
diff: @@ -174,7 +174,8 @@ map<string, vector<float> > MBTR::getK3(const vector<int> &Z, const vector<vecto
  // within the neighbourhood
  const vector<int> &i_neighbours = neighbours[i];
  for (const int &j : i_neighbours) {
  - for (const int &k : i_neighbours) {
  + const vector<int> &j_neighbours = neighbours[j];
  + for (const int &k : j_neighbours) {
  // Only consider triplets that have one atom in the original
  // cell
  if (i < this->interactionLimit || j < this->interactionLimit || k < this->interactionLimit) {
  