Add a warning in Mesh::EnsureNodes if converting a NURBS mesh to a high-order, H1-conforming mesh.
Add a warning in Mesh::EnsureNodes if converting a NURBS mesh
to a high-order, H1-conforming mesh.

mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem