Plan.md

1. Change Node to 3D class - done add copy and assignment

2. Change element Class to General Element class main stuff Connectivity Element type 1D Element 2D Element 1 - POINT - Point Element 2 - LINE - Line Element 3 - TRIANGLE - Triangle Element 4 - QUAD - Quad Element 5 - TETRAHEDRON - Tetra Element 6 - PYRAMID - Pyramid Element 7 - WEDGE - Wedge Element 8 - HEXAHEDRON - Hexa Element static constexpr for no reason

    Functions Basic
        copy constructor
        assignment operator
        <<Operator
        getArea/Volume
        getNPE