- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- Note: mpich now builds libmpi.so instead of libmpich.so

- define both -DMPICH_SKIP_MPICXX and -DOMPI_SKIP_MPICXX regardless of
  using openmpi or mpich. This simplifies the files and does not harm.

- a leftover from the change from class to namespace

- the Tools::Vertices() method for creating a vtkPolyData with the
  given points and a corresponding Verts for the points.

- previously just removed duplicate literals, but now remove any
  duplicates.

- Replace previous wordHashSet implementation with a linear search
  instead. The lists are normally fairly small and mostly just have
  unique entries anyhow. This reduces the overall overhead.

- simplifies their use when reordering lists etc.
  (word, fileName, keyType, wordRe)

- "unfriend" IO operators for string types. They require no internal access

- add compile/uncompile methods to keyType for symmetry with wordRe

- when outputting keyType/wordRe, be more explicit about them using
  writeQuoted()

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- delay dereferencing of optional subRegion entries until an
  objectRegistry is required.

  This improves usabilty when reference objects do not yet exist
  at the time of construction.

- complete any pending initialisation on write().
  Allows lazier evaluation until when surfaces are actually available.

- complete any pending initialisation on write().
  Allows lazier evaluation until when the surfaces are actually needed.

- includes initial relocation of low-level vtu handling.
  Extracted, refactored from the Catalyst function object.

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- reduced clutter when iterating over containers

- previously it was only possible to reset a pointer, but not to
  change a const-reference directly (needed a swap() to do this).

- currently supports pTotal, rhoU.

- makes it easier to implement functionObject or field object removal

- use registry checkOut for removeRegisteredObject function object

The occurrence is from cells with vertices that are shared between two faces
only (these vertices can originate from hex refinement). Decomposing both faces
can occasionally produce triangles with identical vertices and this results in a
non-manifold edge which triggers the erosion procedure.

Avoided by detecting cells with these special vertices and making sure the tet-decomposition
never uses the same points on the faces using them.

Patch contributed by Mattijs Janssens