MeshConverter: let Point know in what worls it lives

    class Point {

    public:

        Point() noexcept = default;

        Point(double px, double py, double pz = 0) noexcept : x(px), y(py), z(pz) {}

        Point(double px, double py, double pz) noexcept : x(px), y(py), z(pz), dim(3){};

        Point(double px, double py) noexcept : x(px), y(py), dim(2){};

        double x{0}, y{0}, z{0};

        unsigned int dim{0};

        friend std::ostream& operator<<(std::ostream& out, const Point& pt) {

            out << "(" << pt.x << "," << pt.y << "," << pt.z << ")";