- was superseded by 'scale' in OCT-2008

- improves input compatibility with existing setups

- the #eval directive is similar to the #calc directive, but for evaluating
  string expressions into scalar values. It uses an internal parser for
  the evaluation instead of dynamic code compilation. This can make it
  more suitable for 'quick' evaluations.

  The evaluation supports the following:
    - operations:  - + * /
    - functions:  exp, log, log10, pow, sqrt, cbrt, sqr, mag, magSqr
    - trigonometric:  sin, cos, tan, asin, acos, atan, atan2, hypot
    - hyperbolic:  sinh, cosh, tanh
    - conversions:  degToRad, radToDeg
    - constants:  pi()
    - misc: rand(), rand(seed)

- more consistent location for oneField, oneFieldField inline definitions

- eliminate nullObjectI.H for more transparency

- regression as a result of changed time-handling from #1418.
  Now cache the fields information internally.

- previously allowed mapped value modification with a const iterator.
  However, this can lead to incorrect access patterns.

  Now tie the constness of the mapped value to that of the iterator.

- Remove deprecated iterator object() method.
  Was only used internally and was superseded by the val() method
  in an earlier version.

ENH: change isPointer to isPointerLike

- can distinguish between real pointers and wrapped pointers

- this largely reverts 3f0f218d and 4ee65d12.

  Consistent addressing with support for wrapped pointer types (eg,
  autoPtr, std::unique_ptr) has proven to be less robust than desired.
  Thus rescind HashTable iterator '->' dereferencing (from APR-2019).

- for special cases when normal writing is to be completely disabled
  and replaced with alternate means (eg, via a function object).

- support "adjustable" as "adjustableRunTime" alias to reduce typing
  for writeControl or outputControl

- use HashTable emplace instead of insert to avoid unneeded argument
  (for HashSet).

- use emplace when generating zero-initialized values for
  HashTable::operator()

- drop unused parameter from Detail::HashTableSingle,
  adjust templates parameter names

- forward HashTable::operator[] to the semantically identical
  HashTable::at() to avoid code duplication

- generated C++ files, but didn't use C++ compiler

- call also be used non-interactively for simple 'one-shot' use of
  OpenFOAM utilities or solvers

STYLE: use dash instead of brackets for '- see www.OpenFOAM.com'

- less cluttered in combination with API information

- makes the intention clearer, allows for future tightening of
  iterator access rules.

- useful for manual handling of string with comments