- Allows passing of additional information (per-face zone ids) or possibly
other things, while reducing the number of arguments to pass.
- In sampledTriSurfaceMesh, preserve the region information that was
read in, passing it onwards via the UnsortedMeshSurface content.
The Nastran surface writer is currently the only writer making use
of this per-face zone information.
Passing it through as a PSHELL attribute, which should retain the
distinction for parts. (issue #204)
