- using a filter such as clip-plane on a multi-port source causes
  inconsistent UPDATE_TIME_STEPS() on each port. This looks like a
  VTK/Paraview bug to me.
  Workaround: check both ports and take the first one that has a value
  different than the last time set.

- objectRegistry gets a rename() that also adjusts the dbDir
- cloud reworked to use static variables subInstance and defaultName.
  This avoids writing "lagrangian" everywhere

string fixes
- avoid masking of std::string::replace in string.H
- avoid old strstream in PV3FoamReader

- OSspecific: chmod() -> chMod(), even although it's not used anywhere

- ListOps get subset() and inplaceSubset() templated on BoolListType

- added UList<bool>::operator[](..) const specialization.
  Returns false (actually pTraits<bool>::zero) for out-of-range elements.
  This lets us use List<bool> with lazy evaluation and no noticeable
  change in performance.

- use rcIndex() and fcIndex() wherever possible.
  Could check if branching or modulus is faster for fcIndex().

- UList and FixedList get 'const T* cdata() const' and 'T* data()' members.
  Similar to the STL front() and std::string::data() methods, they return a
  pointer to the first element without needing to write '&myList[0]', recast
  begin() or violate const-ness.

    - convertPointField caused a seg-fault if the internal field was null
      - attempted to name the vtk object the name of the null field

+ minor clean-up

- can use 'XX.empty()' instead of 'XX.size() == 0', 'XX.size() < 1' or
  'XX.size() <= 0' or for simpler coding.
  It also has the same number of characters as '!XX.size()' and /might/ be
  more readable

- many size checking had 'XX.size() > 0', 'XX.size() != 0', or 'XX.size() >= 1'
  when a simple 'XX.size()' suffices

  Pro: Good delimitation. Good visual distinction. No confusion with normal
       cases, since '{}' characters are excluded by !word::valid()
  Con: Possible quoting issues when creating directly instead of via paraFoam,
       but seemed to work fine with bash TAB completion.

  - handling multiple regions require multiple readers
  - a region is currently recognized by the file name, anything after the
    '=' delimiter (eg, "case=region.OpenFOAM") is used to determine the
    mesh region, but might be changed in the future
    eg, 'case%region', 'case^region', 'case~region', 'case{region}' ...

Note:
  - Having a separate reader for each region instead attempting to handle
    all the mesh regions in a single reader is the better solution.
    It is not only simpler, but allows distinct field selections for
    each region
Todo:
  - Haven't a test for Lagrangian and multi-regions.

  - remove TimeRange property from XML. Not needed for discrete time data
  - represent Lagrangian data as VTK_VERTEX for simple visualization

 - streamlined code somewhat, minor attempt to reclaim some memory
 - now use "mesh parts" for patches/zones/sets/etc throughout to avoid
   ambiguity with mesh regions
 - collect superCells and addPointCellLabels in a class. The old version
   actually seemed to have overwritten the addPointCellLabels with each
   cellSet/cellZone. This means that part of the pointFields would be trashed
   in the combination of polyhedral cells, cellSets/cellZones and internalMesh
 - polyDecomp information for muitiple mesh regions, but not yet exploited
 - pointFields now working for cellZones/cellSets
 - extroplating fields onto walls also works as expected for interpolated
   pointFields
 - added tooltips to reader GUI

TODO:
 - pointFields (real and interpolated) for faceSets/faceZones

  - various GUI properties are now animateable="0"
    (meaning they no longer show up on the time-line)
  - move reader switches to the bottom of the GUI
  - move Lagrangian fields above pointFields for better visibility
  - basic support for multiple clouds
  - filter fields based on selection before looping over all the geometry bits
  - mesh conversion functions now return VTK mesh types for easier handling
  - faceZones mesh conversion had points/faces allocation reversed
  - updateInfo with every call to setTime() that changes the timeIndex
    This seems to be the only way to notice Lagrangian fields
  - restore displaying patchnames that got forgotten in the last commit
  - misc reorganization

  - normal mesh data on port0
  - Lagrangian data on port1
  - no fixed block numbers for dividing internalMesh, patches, zones etc.
    This helps avoid ugly gaps in the multiblock output
  - avoid segfault if Lagrangian fields are converted without positions

  TODO:
  - can we label the output ports?
  - the selection of Lagrangian data and fields is wonky.

  - added printMemory() method to aid debugging memory used
  - call UpdateInformation() if the mesh has changed
  - automatic activation of "internalMesh", "p", "U"
    is suppressed if a fvMesh is cached. Otherwise,
    appearing/disappearing volFields can cause a crash

  Note:
  The message "had to make up a selection value" that sometimes occurs
  seems to be paraview related (see paraview mailing list),

  - vtkPV3Foam get PrintSelf (reduces number of methods)
  - move output data member from vtkPV3Foam -> PV3FoamReader
    in preparation for rewriting output method
  - roughed in code to track mesh/field changes in preparation for rewriting
    output method
  - progress bar with arbitrary values to give the user something to watch

  - avoid code duplication in vtkPV3Foam.C and checkTimeOption.H
  - can also be used in Time::findClosestTime(), but didn't touch that

  - On the first call, select 'internalMesh' and the 'p', 'U' fields.
    This corresponds to a fairly common default case without loading all
    possible fields etc.
  - Include zones should now work without issuing a FatalError when the
    corresponding files are missing. I must have tried too many things
    at once and didn't notice this before.
  - Use ZoneMesh for zone names if the fvMesh is already cached
    (skips re-reading the same files).
  - Change reader description to "OpenFOAM Reader" to distinguish it a bit
    from the vtkOpenFOAMReader built into paraview/vtk
  - Misc. file and method names reorganized

  - Remaining problem:
    mixing internalMesh and cellZones is clunky since there aren't yet
    interpolated point values for cellSets/cellZones. Paraview complains
    about the mismatch, but extracting a block is still okay.

  TODO:
  - multi-port output for Lagrangian
  - hold all the vtk mesh parts (including multiblock) and just pass the
    reference. With this, the pipeline might notice that the geometry is
    actually identical and skip the PVGeometryFilter that takes so long.

previous disabling of the TimeSelection arrays [commit c52b20b..]
resulted in the mesh caching being disabled :(

Simplified code is enabled/disabled by PV3FOAM_TIMESELECTION define.
Might be removed in the future.