message: UI-QT: fixed update of Isosurface renderers when Geometry is changed.
  Before, when changing from 2D to 3D, the isosurfaces would need to be re-added.
diff: @@ -127,14 +127,11 @@ const VFRendering::VectorField * SpinWidget::vectorfield()
  }
  void SpinWidget::addIsosurface(std::shared_ptr<VFRendering::IsosurfaceRenderer> renderer)
  -{
  - if (Geometry_Get_Dimensionality(this->state.get()) == 3)
  {
  this->m_renderers_isosurface.insert(renderer);
  if (m_gl_initialized)
  this->enableSystem(this->show_arrows, this->show_boundingbox, this->show_surface, this->show_isosurface);
  }
  -}
  void SpinWidget::removeIsosurface(std::shared_ptr<VFRendering::IsosurfaceRenderer> renderer)
  {
  @@ -1055,7 +1052,7 @@ void SpinWidget::enableSystem(bool arrows, bool boundingbox, bool surface, bool
  system.push_back(this->m_renderer_boundingbox);
  if (show_surface && (Geometry_Get_Dimensionality(this->state.get()) == 2 || Geometry_Get_Dimensionality(this->state.get()) == 3))
  system.push_back(this->m_renderer_surface);
  - if (show_isosurface)
  + if (show_isosurface && (Geometry_Get_Dimensionality(this->state.get()) == 3))
  {
  for (auto& iso : this->m_renderers_isosurface) system.push_back(iso);
  }
  