- this is a provision for defining execute actions that can be called
  largely independently of the normal time-loop constraints. This can
  be useful to provide hooks for sub-cycling, or to define an action
  that can be triggered manually or on some other event.

This forms part of what is termed 'automatic wall treatment' in the
reference:

    Menter, F., Carregal Ferreira, J., Esch, T., Konno, B. (2003).
    The SST Turbulence Model with Improved Wall Treatment
    for Heat Transfer Predictions in Gas Turbines.
    Proceedings of the International Gas Turbine Congress 2003 Tokyo

Note
    The full 'automatic wall treatment' description also requires use of
    the  Foam::omegaWallFunction with the \c blended flag set to 'on'

omegaWallFunction
- re-instated behaviour when not using 'blended'
- turbulence generation always included when using 'blended'
- 'blended' now true by default

epsilonWallFunction
- re-instated low-Re switching

Minor improvements for redistributePar

See merge request OpenFOAM-plus!181

- list all regions from constant/regionProperties:
     * foamListRegions

- list specific region type from constant/regionProperties:
     * foamListRegions fluid
     * foamListRegions solid

- after redistribution, the old cellProcAddressing etc files are incorrect
  and potentially troublesome.

Henry Weller authored 7 years ago and Andrew Heather committed 7 years ago

so the write thread does not have to do any parallel communication.  This avoids
the bugs in the threading support in OpenMPI.

Patch contributed by Mattijs Janssens
Resolves bug-report https://bugs.openfoam.org/view.php?id=2669

minor improvements in profiling

See merge request OpenFOAM-plus!178

- include amount of free system memory in profiling, which can give an
  indication of when swapping is about to start

- profilingSummary utility to collect profiling from parallel
  calculations. Collects profiling information from processor
  directories and summarize the time spent and number of calls as (max
  avg min) values.

Feature domain decomp (wp05)

See merge request OpenFOAM-plus!163

consolidate surfaceFormats for reading/writing triSurface

See merge request OpenFOAM-plus!174

preliminary improvements for externalCoupled

See merge request OpenFOAM-plus!175

- similar idea as subCycleTime but without sub-dividing the time
  interval or incrementing time itself

- waitForSlave now return a Time::stopAtControls enumeration:

    unknown:     when lockfile has no specially recognized content.
    endTime:     when lockfile contains "status=done"
    writeNow:    when lockfile contains "action=writeNow"
    nextWrite:   when lockfile contains "action=nextWrite"
    noWriteNow:  when lockfile contains "action=noWriteNow"

These values can be used by the caller to terminate the master
(OpenFOAM) as desired in response to information placed there by the
slave process.

- use a Pair<scalar> with first() / last() residuals

- expose the names of write and stopAt controls for reuse elsewhere and
  provide a stopAtControls enum for 'unknown'

- track the requested number of sub-cycles (was previously a bool)

- found() method for consistency with other classes

- operator()(name, deflt) for similarity to lookupOrDefault,
  but without a dictionary

- the readList<T>(Istream&) function was introduced to handle command
  -options with either a single or a list value, but was also used for
  the #remove dictionary directive. However, the parsing was fragile
  if the list did not start with a '('.
  Now handle command-line arg/option list directly (via ITstream)
  and #remove with special-purpose reading of a string or word list.

  This removes ambiguity and reduces potential future problems.

STYLE: use ITstream instead of IStringStream for command-line lookups

- parses directly to a tokenList without a string copy.