- having whitespace in fileName can be somewhat fragile since it means
  that the fileName components do not necessarily correspond to a
  'Foam::word'. But in many cases it will work provided that spaces
  are not present in the final portion of the simulation directory
  itself.

    InfoSwitches
    {
        // Allow space character in fileName (use with caution)
        allowSpaceInFileName    0;
    }

- now use doClean=true as default for fileName::validate(). Was false.

  Unlike fileName::clean() this requires no internal string rewrite
  since the characters are being copied.  Also handle any path
  separator transformations (ie, backslash => forward slash) at the
  same time. This makes it resemble the std::filesystem a bit more.

oversetInterpolationSuppressed dict.

- can be useful for retrieving the compilation flags for use with other
  make systems (eg, cmake)

  * wmake -show-compile   (C++ not C)
  * wmake -show-cxx
  * wmake -show-cxxflags

- operators are still incomplete, as are dimensioned fields,
  field-fields etc.

- split complexFields into separate complexField, complexVectorField files

- add construction from and conversion to std::complex, which allows
  easier wrapping of functions

- add Foam:: functions for complex versions of sin, cos, ...

- grid(i,j,k) method for returning the grid point at an i-j-k location

- The 'used()' method was for transitional compatibility with the now
  defunct PackedBoolList.

  The canonical method name for returning a labelList of 'on' bits is
  toc().

- was historically defined as (1 1), but it is more consistent with
  the concept of one to have a real component only.

  Now defined as (1 0):  1+0i

STYLE: remove obscure '!' operator for complex conjugate

- either use the member function or the '~' operator

Snappy hex mesh proximity check

See merge request OpenFOAM-plus!249

- construct/assign from Zero