fixes #560

Now we directly releate the intersected face triangle to the tet of the
cell the point is on/in. We hope that the tracking handles this ok. Fixes #549.

- assists when building simple hand-rolled parsers.
  Also add string::split() taking a sub-string for the delimiter.

- actually prevent this type of thing:

      Switch sw;
      sw = "none";

  without relinquishing automatic conversion to/from bool.
  Nonetheless, make construct from string explicit.

- Added some minor optimization for the lookup of the switch names.

ENH: use std C++ for conversions instead of sscanf()

Bug pstream token sending

See merge request !140

- access tokenType enum values more consistently.

- the (global) associative array requires bash >= 4.2

- the tokenType was being send via write(char), which includes
  isspace filtering. If the tokenType enumeration coincides
  with a whitespace character, it would be suppressed.

  Now add character directly to the buffer.

STYLE: some additional minor private methods to help refactoring

- readStringFromBuffer, writeStringToBuffer for common string
  operation.

Feature robuster IOobjectList construction

See merge request !134

Feature bash completion

See merge request !137

- this reduces the number of functions and allows lazy loading of
  completion options, which makes it easy to quickly add any other
  OpenFOAM application in completion.

  The generic '_of_complete_' function handles (bash) completion for
  any OpenFOAM application. On the first call for any particular
  application, it retrieves the available options from the application
  help output and adds this information to its environmental cache for
  subsequent use.

- Tcsh completion uses the same function via a bash wrapper.
  But since its wrapper is transient, the on-the-fly generation would
  be less efficient. For this case, a pre-generated completion_cache
  can be used, which is generated with

      bin/tools/foamCreateCompletionCache

STYLE: New syntax compatible with v1706 (Fixes #548)

See merge request !131

- handles the case where we are currently completing something that
  does not appear to be an option. For example,

      foamDictionary -expanded someD[TAB]

  should complete the filename, not present more options.

- and other code style adjustments

- The logic for switching input-mode was previously completely
  encapsulated within the #inputMode directive, but without any
  programming equivalent. Furthermore, the encapsulation in inputMode
  made the logic less clear in other places.

  Exposing the inputMode as an enum with direct access from entry
  simplifies things a fair bit.

- eliminate one level of else/if nesting in entryIO.C for clearer logic

- for dictionary function entries, simply use
  addNamedToMemberFunctionSelectionTable() and avoid defining a type()
  as a static. For most function entries the information is only used
  to get a name for the selection table lookup anyhow.

- although this has been supported for many years, the tutorials
  continued to use "convertToMeters" entry, which is specific to blockMesh.
  The "scale" is more consistent with other dictionaries.

ENH:
- ignore "scale 0;" (treat as no scaling) for blockMeshDict,
  consistent with use elsewhere.

Style string methods

See merge request !136

- currently no cleanup of completions when deactivating an OpenFOAM
  tcsh environment

- tab completion with directories adds a space after the slash, which
  makes navigation a bit annoying.

- useful operations for other string representations of fileName types.

  The return type is in general a std::string with any narrowing
  being done by the caller on the return value.

- consolidate word::validated() into word::validate() and also allow
  as short form for string::validate<word>(). Also less confusing than
  having similarly named methods that essentially do the same thing.

- more consistent const access when iterating over strings

- add valid(char) for keyType and wordRe

- can inadvertently arise from TAB-completion, but an option without a
  name doesn't make sense, we trap this and emit a warning.