Fix/interior node orderings

This MR addresses issue 12 and fixes the node orderings for electrostatic and fekete triangles. The poly evenly spaced does not require fixing. The Electrostatic tet does require fixing in the future but as we don't support volume curvature, its not needed yet.

This will break meshes with distributions of these types. But this effect should be minimal because most meshes come from gmsh and don't use them. Those that do can be fixed by deleting the face curvature tag or remaking the mesh.

Because I forgot to do this in the right place, this cannot be merged before MR 527 easily.