- need additional tolerance when comparing time values to those
  stored in the fieldDict (both less and equal operators)

ENH: improved handling of regIOobject deletion (#1276)

See merge request OpenFOAM-plus!263

ENH: FO: Lamb vector and its divergence

See merge request OpenFOAM-plus!245

  - If applied:
      This commit allows the user to compute:
        - the Lamb vector (https://en.wikipedia.org/wiki/Lamb_vector),
        - on-the-fly or via postProcess utility
        - for a given volVectorField (one per functionObject entry)

  - Why:
      The motivation is the literature-reported quantitative connection
      between the Lamb vector (divergence) and the spatially localised
      instantaneous fluid motions, e.g. high- and low-momentum fluid
      parcels, which possess considerable level of capacity to affect
      the rate of change of momentum, and to generate forces such as drag.

  - Verification:
      - Smooth-wall plane channel flow case (Moser et al. 1999) by
          # Curtis et al. (2008) On the Lamb vector divergence
            in Navier–Stokes flows, doi:10.1017/S0022112008002760

  - What's next:
      - The verification-show case
      - Extended code guide entry titled "Lamb vector"

- remove registration and ownership before deleting a regIOobject
  from within objectRegistry to avoid possible recursion.

- regIOobject destructor now removes any registered object from
  registry regardless if ownedByRegistry or not. It also removes
  always removes the ownership flag to avoid possible recursion.

- the regIOobject::checkOut() now unconditionally clears file watches.
  These will only be there if the object is registered (a no-op for an
  unregistered object), but this additional safety is needed to manage
  case where the registration has been modified elsewhere (eg, by the
  objectRegistry).

Feature complex cleanup

See merge request OpenFOAM-plus!264

ENH: define addition/subtraction operations for scalar and complex

- required since construct complex from scalar is explicit
- additional tests in Test-complex

- can additionally relinquish the registered state as well as
  ownedByRegistry state

- when a single (non-regex) source field is specified, it is now
  possible to specify the result name without any '@@' substitution
  tokens

- forces c++DBUG='-DFULLDEBUG -g -O0' for the compilation, to allow
  localized debugging during development without file editing and
  while retaining the WM_COMPILE_OPTION (eg, Opt)

  Note that switching between 'wmake' and 'wmake -debug' will not
  cause existing targets to be rebuilt. As before, these are driven by
  the dependencies. An intermediate wclean may thus be required.

- in case an individual geometry element has render issues in parallel

- additional debug information

Calculates and outputs the pressure fields p_rgh and ph_rgh based on the
option that was previously hard-coded in the fireFoam solver

Usage
    Example of function object specification to calculate hydrostatic pressure:
    \verbatim
    hydrostaticPressure1
    {
        type        hydrostaticPressure;
        libs        ("libinitialisationFunctionObjects.so");
        ...
    }
    \endverbatim

    Where the entries comprise:
    \table
        Property     | Description             | Required    | Default value
        log          | Log to standard output  | no          | yes
        p_rgh        | Name of p_rgh field     | no          | p_rgh
        ph_rgh       | Name of ph_rgh field    | no          | ph_rgh
        pRef         | Name of pressure ref field | no       | pRef
        rho          | Name of density field   | no          | rho
        U            | Name of velocity field  | no          | U
        gh           | Name of gravity*height volume field  | no | gh
        ghf          | Name of gravity*height surface field | no | ghf
        nCorrectors  | Number of correctors when solving ph_rgh | no | 5
    \endtable

Note
    Calculates the hydrostatic pressure on construction/re-initialisation;
    the execute and write functions are not used.

- error trapped by C++11 regex

- was missing range setting for the colour lookup table

- generalize identity matrix constructors for non-scalar types

- add constructors using labelPair for the row/column sizing information.
  For a SquareMatrix, this provides an unambiguous parameter resolution.

- reuse assignment operators

STYLE: adjust matrix comments

- additional operators:
  + compound assignment
  + inner product: operator&
  + outer product: operator^

- additional functions:
   - MatrixBlock methods: subColumn, subRow, subMatrix
   - L2 norms for matrix or column
   - trace, diag, round, transpose

- MatrixBlock methods: col(), block() are deprecated since their
  access patterns with (size, offset) are unnatural/unwieldy.

- verifications by test/Matrix/Test-Matrix

- make parallelProjection default (was previously mandatory)

- add vsmall pTraits for scalars
- report the solve scalar in buildArch information

- for most functions the input type and return type are identical,
  but MinMax, sumMag are not.

- previously returned scalar, but now return pTraits cmptType
  which is the same as scalarProduct / outerProduct type.

- eg pTraits<complex>::zero, pTraits<complex>::one instead.
  This is consistent with other primitives such as scalar, label etc.

- make names consistent with lduMatrix
    A*x  => Matrix::Amul
    AT*x => Matrix::Tmul  (same as x*A)

- reduces installation clutter, allows easier cross-referencing

- remove older deprecated scripts (foamDebugSwitches, foamGraph*)

- when windows portable executables (.exe or .dll) files are loaded,
  their dependent libraries not fully loaded. For OpenFOAM this means
  that the static constructors which are responsible for populating
  run-time selection tables are not triggered, and most of the run-time
  selectable models will simply not be available.

Possible Solution
=================

  Avoid this problem by defining an additional library symbol such as
  the following:

      extern "C" void libName_Load() {}

  in the respective library, and tag this symbol as 'unresolved' for
  the linker so that it will attempt to resolve it at run-time by
  loading the known libraries until it finds it. The link line would
  resemble the following:

      -L/some/path -llibName -ulibName_Load

  Pros:
    - Allows precise control of forced library loading

  Cons:
    - Moderately verbose adjustment of some source files (even with macro
      wrapping for the declaration).
    - Adjustment of numerous Make/options files and somewhat ad hoc
      in nature.
    - Requires additional care when implementing future libraries and/or
      applications.

  - This is the solution taken by the symscape patches (Richard Smith)

Possible Solution
=================

  Avoid this problem by simply force loading all linked libraries.
  This is done by "scraping" the information out of the respective
  Make/options file (after pre-processing) and using that to define
  the library list that will be passed to Foam::dlOpen() at run-time.

  Pros:
    - One-time (very) minimal adjustment of the sources and wmake toolchain
    - Automatically applies to future applications

  Cons:
    - Possibly larger memory footprint of application (since all dependent
      libraries are loaded).
    - Possible impact on startup time (while loading libraries)
    - More sensitive to build failures. Since the options files are
      read and modified based on the existence of the dependent
      libraries as a preprocessor step, if the libraries are initially
      unavailable for the first attempt at building the application,
      the dependencies will be inaccurate for later (successful) builds.

  - This is solution taken by the bluecape patches (Bruno Santos)

Adopted Solution
================

  The approach taken by Bruno was adopted in a modified form since
  this appears to be the most easily maintained.

Additional Notes
================

  It is always possible to solve this problem by defining a corresponding
  'libs (...)' entry in the case system/controlDict, which forces a dlOpen
  of the listed libraries. This is obviously less than ideal for large-scale
  changes, but can work to resolve an individual problem.

  The peldd utility (https://github.com/gsauthof/pe-util), which is
  also packaged as part of MXE could provide yet another alternative.
  Like ldd it can be used to determine the library dependencies of
  binaries or libraries. This information could be used to define an
  additional load layer for Windows.