STYLE: renamed periodicHill createPlots -> plot for consistency

TUT: use nutLowReWallFunction for bump2D

- required for the new nutWallFuncs hierarchy

- enables future use of precision adaptors

- we know they have already protected by an is_contiguous check,
  so the class-memaccess warning/error can be suppressed.

- adjust known gcc/clang compiler versions

For example,

   $ someSolver -info-switch writeOptionalEntries

- note that values changed via the command-line are changed after the
  etc/controlDict entries, but *before* any case-local
  system/controlDict entries.

  However, in many testing cases the command-line options eliminate
  the need for such local file modifications.

ENH: cleanup handling of local debug switches in Time

- add as methods directly on simpleObjectRegistry to avoid code
  duplication

STYLE: adjust internal naming of ITstream parameters

- now reports the dictionary, entry, default. For example,

  Dictionary: <case>/0/nut.boundaryField.wall Entry: Cmu Default: 0.09
  Dictionary: <case>/0/nut.boundaryField.wall Entry: kappa Default: 0.41
  Dictionary: <case>/0/nut.boundaryField.wall Entry: E Default: 9.8

- suppress reporting for debug, optimisation switches since this
  generates extremely noisy output

- cannot rely on the entries having a keyword method

STYLE: apply consistent hash table sizing for debug objects

It was tracking to find the wanted sampling location. This tracking
was using the offsetted seed point instead of the offsetted wanted
sampling point.

- cannot change stream compression after construction.

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