message: Use boolean for pq_handle data type and specific update use for CGAL>=5.5
diff: @@ -172,7 +172,7 @@ typename GeometricSimplifiableComplex::Vertex_handle> {
  };
  typedef CGAL::Modifiable_priority_queue<Edge_handle, Compare_cost, Undirected_edge_id> PQ;
  - typedef typename PQ::handle pq_handle;
  + typedef bool pq_handle;
  // An Edge_data is associated with EVERY edge in the complex (collapsible or not).
  @@ -196,7 +196,7 @@ typename GeometricSimplifiableComplex::Vertex_handle> {
  }
  bool is_in_PQ() const {
  - return PQHandle_ != PQ::null_handle();
  + return PQHandle_ != false;
  }
  void set_PQ_handle(pq_handle h) {
  @@ -204,7 +204,7 @@ typename GeometricSimplifiableComplex::Vertex_handle> {
  }
  void reset_PQ_handle() {
  - PQHandle_ = PQ::null_handle();
  + PQHandle_ = false;
  }
  private:
  @@ -238,16 +238,22 @@ typename GeometricSimplifiableComplex::Vertex_handle> {
  }
  void insert_in_PQ(Edge_handle edge, Edge_data& data) {
  - data.set_PQ_handle(heap_PQ_->push(edge));
  + heap_PQ_->push(edge);
  + data.set_PQ_handle(true);
  ++current_num_edges_heap_;
  }
  void update_in_PQ(Edge_handle edge, Edge_data& data) {
  +#if CGAL_VERSION_NR < 1050500000
  data.set_PQ_handle(heap_PQ_->update(edge, data.PQ_handle()));
  +#else
  + heap_PQ_->update(edge);
  +#endif
  }
  void remove_from_PQ(Edge_handle edge, Edge_data& data) {
  - data.set_PQ_handle(heap_PQ_->erase(edge, data.PQ_handle()));
  + heap_PQ_->erase(edge);
  + data.set_PQ_handle(false);
  --current_num_edges_heap_;
  }
  