ENH: added scalarField hypot() function

- Now accept '/' when reading variables without requiring
  a surrounding '{}'

- fix some degenerate parsing cases when the first character is
  already bad.

  Eg, $"abc" would have previously parsed as a <$"> variable, even
  although a double quote is not a valid variable character.

  Now emits a warning and parses as a '$' token and a string token.

- avoid the name eval(), since this collides with the identical
  macro name if m4 is used sometime in the future

- add toScalar evaluation, embedded as "${{EXPR}}".

  For example,

    "repeat ${{5 * 7}} times or ${{ pow(3, 10) }}"

- use direct string concatenation if primitive entry is only a string
  type. This prevents spurious quotes from appearing in the expansion.

     radius  "(2+4)";
     angle   "3*15";
     #eval   "$radius*sin(degToRad($angle))";

     We want to have
         '(2+4)*sin(degToRad(3*15))'
     and not
         '"(2+4)"*sin(degToRad("3*15"))'

ENH: code refactoring

- refactored expansion code with low-level service routines now
  belonging to file-scope. All expansion routines use a common
  multi-parameter backend to handle with/without dictionary etc.
  This removes a large amount of code duplication.

- add floor/ceil/round methods
- support evaluation of sub-strings

STYLE: add blockMeshDict1.calc, blockMeshDict1.eval test dictionaries

- useful for testing and simple demonstration of equivalence

- SubField and SubList assign from zero
- SubField +=, -=, *=, /= operators

- SubList construct from UList (as per SubField)

  Note: constructing an anonymous SubField or SubList with a single
  parameter should use '{} instead of '()' to avoid compiler
  ambiguities.

- drop plugin support for Qt4 (old paraview)

- handle upcoming changes in VTK version naming in CMake files
  * VTK_MAJOR_VERSION becomes VTK_VERSION_MAJOR etc.

  - Improves header file documentations
  - Adds const specifier to various objects
  - Allows various model constants to be user-defined
  - Changes from lookupOrDefault() to getOrDefault()
  - Consistent namespace usage:
    - If the WF belongs to only Foam:: namespace, use Foam:: explicitly
    - If the WF belongs to more than one namespaces, put the WF in namespace
      parentheses
  - Adds the missing dashes in comments required by Doxygen
  - Corrects capitalisation in comments
  - The terminology 'viscous sublayer' was preferred over 'laminar sublayer'
    due to the fact that the sublayer is not laminar.
  - The order of initialisation of fields is changed to be the same across all.

OpenFOAM.org commits for
  src/TurbulenceModels/turbulenceModels/derivedFvPatchFields/wallFunctions
were reviewed.

The parts of the commits made by OpenFOAM.org removing various code
duplications across wall functions were picked up by keeping the remaining
functionalities the same.

The duplications were mainly due to:
  - wall function model coefficients
  - yPlusLam(), checkPatch(), write() methods

The duplications were united under the base nutWallFunction.

- did not perform as well as desired. Slated for replacement with a
  different approach.

- since a zero-sized FixedList is disallowed, the accessors to the
  first/last elements are always known.

  This allows Pair second() to be noexcept as well (as per Tuple2)

- use git show --ignore-space-change when examining

- 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)