message: Add missing virtual mesh destructors
diff: @@ -71,6 +71,8 @@ namespace RINGMesh {
  friend class MeshBaseBuilder ;
  public:
  + virtual ~MeshBase() = default ;
  +
  virtual void save_mesh( const std::string& filename ) const = 0 ;
  /*!
  @@ -142,19 +144,14 @@ namespace RINGMesh {
  friend class Mesh0DBuilder ;
  public:
  - virtual ~Mesh0D()
  - {
  - }
  + virtual ~Mesh0D() = default ;
  static Mesh0D* create_mesh( const MeshType type ) ;
  protected:
  /*!
  * @brief Mesh0D constructor.
  */
  - Mesh0D()
  - : MeshBase()
  - {
  - }
  + Mesh0D() = default ;
  } ;
  using Mesh0DFactory = GEO::Factory0< Mesh0D > ;
  #define ringmesh_register_mesh_0d(type) \
  @@ -169,6 +166,8 @@ namespace RINGMesh {
  friend class GeogramMeshBuilder ;
  public:
  + virtual ~Mesh1D() = default ;
  +
  static Mesh1D* create_mesh( const MeshType type ) ;
  /*
  @@ -247,6 +246,8 @@ namespace RINGMesh {
  friend class Mesh2DBuilder ;
  public:
  + virtual ~Mesh2D() = default ;
  +
  static Mesh2D* create_mesh( const MeshType type ) ;
  /*!
  @@ -588,6 +589,8 @@ namespace RINGMesh {
  friend class Mesh3DBuilder ;
  public:
  + virtual ~Mesh3D() = default ;
  +
  static Mesh3D* create_mesh( const MeshType type ) ;
  /*!
  