Add the vtk mapped data array MeshNodalCordinates.

This data mapper allows you to map external data into the
vtkDataArray.
This in turn allows you to interface with vtk without
repacking the simulatordata.

Clean up and implement a pimpl VtkRenderer to hide
redering implementation.

Replace core::StdVector3d with std::vector<core::Vec3d>

because eigen 3d vector array is aligned
by default so no special allocator is needed. See core::StdVector3d
for more details.