add Tests/NumLib in CMake
add a test for ShapeQuad4
add a shape function class for quad4
Add NumLib to doxygen inputs.
[NL] ShapeQuad4 correct argument names.
[NL] ShapeQuad4. Small numerical improvements removing for-loop.
[NL] Improve Doxygen output.
Merge pull request #216 from endJunction/Quad4ShapeFunctions

Quad4 shape functions