- permits use of these checks for routines wishing to handle their own
  logic.

- now applicable to labelLists.

Note:
  in some situations it will be more efficient to use
  Foam::identity() directly. Eg,

     globalIndex globalCells(mesh.nCells());
     ...
     labelList cellIds
     (
         identity(globalCells.localSize(), globalCells.localStart())
     );

- this helps for trapping unguarded dictionary lookups.

- The change from "solver" to "motionSolver" has not been
  applied consistently for all types of motion solvers.

- previously simply read files until the input stream went bad and no
  more lines could be read.  With the more stringent checking of
  values read (commit 0ce7e364) this approach causes problems.

  Use the underlying tokenizer instead to decide about termination.

- SubField<vector> vs Field<vector>

- for space-savings the VTK fields are normally written as 'float'
  rather than double. When a double field contains very large values,
  these can result in a overflow when converted to float.

  Now trap these with the appropriate numeric limits.
  No warning when these values are clipped: it should be readily
  apparent from the output.

ENH: handle symmTensor component swapping directly on VTK output.

- use VTK output routines in vtkSurfaceWriter to benefit from the
  above changes

- a failed attempt to read a value (eg, word, label, scalar) from a
  stream now always provokes a FatalIOError.
  This helps avoid some difficult to trace input errors.

- preliminary work to #1057

- add dictionary selectable format (ascii|binary) to
  VTKsurfaceFormat, VTPsurfaceFormat

Feature topo set improvements (issue #1060)

See merge request OpenFOAM-plus!216

type sampled is the equivalent of 'mappedField' bc
functionality - it samples a registered field on a
different region/patch/cells.

- make topoSet set/unset methods virtual to allow overloading

- old 'DELETE' enum was easily confused with 'REMOVE', which removes
  the set, not the elements from the set.

- provide corresponding subtractSet() method

STYLE: HashSet set/unset instead of insert/erase methods in topoSetSource

- simplifies switching to/from bitSet storage

- add intermediate classes topoSetCellSource, topoSetFaceSource,
  topoSetPointSource and corresponding New() factories