- for quantities such as face area/normals etc, it can be useful to
  calculate directly and avoid the overhead of caching all the values.

STYLE: comments, use HashTable lookup() method in whichPoint()

- this allows more use of the runTimePostProcessing functionObject
  that will fail more gracefully if the proper version could not be
  built.

  The dummy functionObject simply emits a message that it is not available.

- primarily for handling cmake replacement libraries

- this is identical to either of these solutions:

     * getEnv("FOAM_CASE")
     * stringOps::expand("<case>")

  but with a closer resemblance to argList or Time globalPath(),
  which makes the intent clearer.
  Avoids using raw strings in the caller, which improves compile-time checks.

  Used in situations where a class has no derivation path or other
  access to a time registry or command args.

- provide relativePath() for argList and for Time.
  These are relative to the case globalPath().
  Eg,

     Info<< "output: " << runTime.relativePath(outputFile) << nl;

- partial solution for issue #1091

  This generates file properties that are case-relative,
  Eg,

      plane0
      {
          p
          {
              file "<case>/postProcessing/plane0/1/p_plane0.vtk";
          }
          U
          {
              file "<case>/postProcessing/plane0/1/U_plane0.vtk";
          }
      }

   This allows the case to be moved elsewhere and still find its files.

   This functionality was previously added for vtkCloud, but now also
   applies to streamLine, sampledSets and sampledSurfaces

- optionally replace stripped parent directory with the \<case\> shortcut

    "/this/path/and/subdirs/name"

    relative("/this/path")        -> "and/subdirs/name"
    relative("/this/path", true)  -> "\<case\>/and/subdirs/name"

- accept origin or centre, as per other geometric entities

- it is sufficient to provide the total number of times that findBinary()
  failed instead of flooding the screen with messages

  Full verbose warnings still emitted when debugging is on.

- can occur if MPI has be initialized for communication but OpenFOAM
  itself is operating in serial mode and thus did not attach any
  MPI buffers.

- regression was introduced by 628b2445

- now use findEtcEntry() instead to handle file or directory.

  Added findEtcEntries(), which provides provides a common code basis
  for findEtcDirs(), findEtcFiles() ...

- this simplifies use of a unified test for directory or file.

      fileName::Type what = myfile.type(true, true);
      if (what == FILE) ...
      if (what == DIRECTORY) ...

- Use distinct bit values for fileName::Type, for possible use in
  the future.

- related to issue #1121, since we need a more flexible way of
  expanding file or directory.

  An alternative would be to add checkGzip to Foam::exists() and
  Foam::type() functions, but that would make the code there more
  confusing and in the fileHandler classes.

- for some special cases we wish to mark command-line arguments as
  being optional, in order to do our own treatment. For example,
  when an arbitrary number of arguments should be allowed.

  Now tag this situation with argList::noMandatoryArgs().
  The argList::argsMandatory() query can then be used in any further
  logic, including the standard default argument checking.

- with the new default check, can consolidate the special-purpose

      "setRootCaseNonMandatoryArgs.H"

  into the regular

      "setRootCase.H"

- revert to a simple "setRootCase.H" and move all the listing related
  bits to a "setRootCaseLists.H" file. This leaves the information
  available for solvers, or whoever else wishes, without being
  introduced everywhere.

- add include guards and scoping to the listing files and rename to
  something less generic.

     listOptions.H -> setRootCaseListOptions.H
     listOutput.H  -> setRootCaseListOutput.H

- Now also responds to the contents of the trigger file,
  processing action= contents similar to used with external coupling.

  Previously it only handled an action that was defined in the
  dictionary. With this update, the user can chose a diferent action
  simply by echoing the appropriate action string into the trigger
  file.

- similar to the foamEtcFile script -mode=... option, the specific
  search location (user/group/other) can now also specified for
  string expansions and as a numerical value for etcFile()

  For example, if searching for group or other (project) controlDict,
  but not wishing to see the user controlDict:

    1.  foamEtcFile -mode=go controlDict

    2.  fileName dictFile("<etc:go>/controlDict");
        dictFile.expand();

    3.  etcFile(controlDict, false, 0077);

  The default behaviour for searching all contexts is unchanged.

    1.  foamEtcFile controlDict

    2.  fileName dictFile("<etc>/controlDict");
        dictFile.expand();

    3.  etcFile(controlDict);

- also replaced a few instances of readIfPresent with opt<> for
  constant values.