- 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.