- extends existing surfaceFormats to include surfaces with
  labelledTri as their face representation.

This reverts commit c5bea524.

This reverts commit b18f6cc1.

- treat 'ofs' IO just like any other format
- dropped BasicMeshedSurface, since MeshedSurface can now also have zero or
  more zones
- UnsortedMeshedSurface is a special type of MeshedSurface with zero zones,
  but with additional zoneId labels
- use MeshedSurfaceProxy for writing surfaces with points/faces/zones and
  optional faceMap - provides output interface for MeshedSurface,
  UnsortedMeshedSurface and surfMesh.
- simplify output to filenames only, I can't see that the Ostream
  is needed anywhere
- surfMesh renaming now works, after the objectRegistry fix

- add placeholder BoundaryMesh to surfMesh allows us to drop the
  SurfGeoMesh class and just reuse the GeoMesh class.
  Do the same for triSurface.

- renamed surface regions (formerly patches or groups) to surfZone.

- added surfMesh, but without any of the patch information needed to make it
  useful for finiteArea.

- promoted coordinateSystem transformation to surfaceMeshConvert and moved
  old to surfaceMeshConvertTesting.

- ditched PrimitivePatchExtra in favour of a PatchTools class that is
  currently just a collection of static functions. They could equally well
  live within PrimitivePatch itself, but isolated also has its advantages.

- MeshedSurface, UnsortedMeshedSurface now have 'regions' instead of
  'patches' since they are more like a faceZone for meshed surfaces than
  patches. This might avoid confusion at a later stage.

 - all formats except ftr and gts are now read as MeshedSurface (thus sorted
   immediately). Avoid unnecessary sorting during construction though.
 - moved cleanup routines completely into PrimitiveMeshedSurface

 - optimized stl reading to skip sort if possible

 - use new HashSet capabilities and sortedOrder function
 - make STL format a MeshedSurface instead of an UnsortedMeshedSurface for
   better (MeshedSurface) reader efficiency

 - added protected storedPoints(), storedFaces() functions for non-const
   access to the data. Mixing protected non-const versions and public const
   versions of the same method does not agree with the compiler
 - better handling of triFace/face distinction

  - neither class names, nor the typedefs for the <face> and <triFace>
    instances are really decided

  - keyedSurface is similar to triSurface, but uses faces
  - meshedSurface is sorted in regions and should be more memory efficient
  - surfMesh is the placeholder name for an OpenFOAM native surface format