message: Code review: add some comments about range.begin() and range.end()
diff: @@ -124,18 +124,22 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
  // Iterator over the simplex tree
  typename std::vector<Simplex_handle>::const_iterator get_filtration_iterator_begin() {
  // Base::initialize_filtration(); already performed in filtration_simplex_range
  + // this specific case works because the range is just a pair of iterators - won't work if range was a vector
  return Base::filtration_simplex_range().begin();
  }
  typename std::vector<Simplex_handle>::const_iterator get_filtration_iterator_end() {
  + // this specific case works because the range is just a pair of iterators - won't work if range was a vector
  return Base::filtration_simplex_range().end();
  }
  Skeleton_simplex_iterator get_skeleton_iterator_begin(int dimension) {
  + // this specific case works because the range is just a pair of iterators - won't work if range was a vector
  return Base::skeleton_simplex_range(dimension).begin();
  }
  Skeleton_simplex_iterator get_skeleton_iterator_end(int dimension) {
  + // this specific case works because the range is just a pair of iterators - won't work if range was a vector
  return Base::skeleton_simplex_range(dimension).end();
  }
  };
  