- unfriend HashSet, HashTable IO operators

- global min(), max(), minMax() functions taking a labelHashSet and an
  optional limit. For example,

      labelHashSet set = ...;

      Info<< "min is " << min(set) << nl;
      Info<< "max (non-negative) " << max(set, 0) << nl;

- make HashTable iterator '->' dereferencing more consistent by also
  supporting non-pointer types as well.

- read HashTable values in-situ to avoid copying

- the Enum::readEntry() method was previously as bit sloppy with
  respect to the enumeration that it accepted. If the input was
  non-mandatory, typos would go unnoticed. Now tighten things so that
  if an enumeration is found, it must also be valid.

STYLE: remove unused/deprecated Enum::lookupOrFailsafe() method

- this was only used in a few places internally in 1712 and 1806 but
  has since then been superseded by getOrDefault() with an optional
  'failsafe' flag.

- previously deprecated and slated for removal in 2018-03

- add triSurface::subsetMesh single-parameter variant

- An identity is often useful when generating connectivity and offset
  information.

- The optional repeat value for vtk::write() allows it to also be used
  as a fill method.

- now catch these and emit a warning.
  Still need to investigate the root cause in the caller(s) or regionSplit.

- the behaviour of std::rename with overwriting an existing file is
  implementation dependent:
    - POSIX: it overwrites.
    - Windows: it does not overwrite.

- for Windows need to use the ::MoveFileEx() routine for overwriting.

  More investigation is needed for proper handling of very long names.

- this cannot be left as a configurable value (on windows), since it
  needs to be enabled even prior to reading the etc/controlDict file,
  in case the OpenFOAM installation path itself contains spaces.

Modifications to help avoid inadvertent overwriting of tutorialsTest:

- new '-force' option to overwrite existing directory

- generate a 'tutorialsTest/Alltest' script that disallows the
  possibilty of self-recursion

- reverse mapping for the original point ids. This can be useful
  when searching a subset of points, but needing to store access to
  the original point index.

- move constructor.

- Allow use/not-use subset as an optional constructor argument for
  more convenient caller logic.

- mingw uses 32-bit long regardless of -m32 or -m64 setting

- when searching for a file that may not actually exist,
  the short-cut optimization could lead to the 'constant' directory
  being ignored.

STYLE: simplify logic in points0MotionSolver::points0IO

- the scotch interface still uses non-const pointers when passing in
  values. For the ConstPrecisionAdaptor this means that we need to cheat
  with a constCast(). Using ref() will rightly trigger complaints about
  trying to modify a const object.

BUG: DimensionedField - register new field if it does not have the same name as the copy - see #1348

- add PDRblockMeshDict example for cavity

- reduced clutter. Mostly only need to scan source tree.

- 00-dummy: use wmake/src/Allmake to get native (not cross-compiled)
  wmake toolchain binaries

- reduced clutter. Mostly only need to scan source tree.

- 00-dummy: use wmake/src/Allmake to get native (not cross-compiled)
  wmake toolchain binaries

- don't need extra nullptr check for some cases. Less clutter.

- changed for 1906 to have a regIOobject always cleanup its
  objectRegistry entry. No need to explicitly 'release' ownership
  for this to now happen.

- doxygen formatting for MeshObject

Caveat: The -Wdeprecated-copy produces many, many compiler warnings

TODO: need to revisit