/// The default implementation is to issue 'delete this'
/// but it can be redefined in inherited classes to handle special deletion mechanisms (e.g. ref counting, private destructors, such as vtk objects deletion with method Delete, etc.).
/// \return The number of remaining references on the object after the call (if meaningfull...): used by bbtk to warn a user if another smart pointing system is still holding the object...
/// The default implementation is to issue 'delete this'
/// but it can be redefined in inherited classes to handle special deletion mechanisms (e.g. ref counting, private destructors, such as vtk objects deletion with method Delete, etc.).
/// \return The number of remaining references on the object after the call (if meaningfull...): used by bbtk to warn a user if another smart pointing system is still holding the object...