This is an intermediate implementation until there is the final cell
data implementation in MeshLib.

I had to introduce a const reference value access method to Element.

There is lots of boilerplate code which is required, see also
https://github.com/Kitware/VTK/blob/master/IO/Exodus/vtkCPExodusIINodalCoordinatesTemplate.h

Started implementing mesh node coordinates wrapper.

Conflicts:
	CMakeLists.txt