openfoam: tune parser handling of string lists in dictionaries

- While any particular OpenFOAM class using dictionary input
  knows what to expect, our parser does not or cannot.

  For an entry with a list of words, it could have two equivalent
  forms:

      1.  keyword  (abc def);
      2.  keyword  2(abc def);

  The parser tokenizes these as

      1.  STRINGLIST
      2.  LABEL STRINGLIST

  Instead of making the parser itself more aggressive, settle for
  fixing up the parse result. When a dictionary entry matches that
  pattern (ie, has label + stringlist and the sizes match), drop
  the redundant size token.

  To be a bit more conservative, limit the fixup to entries that
  contains no other tokens.

BUG: the token IsLabel() condition was incorrect/overly aggressive

- align some token methods with OpenFOAM equivalents.
  Eg, IsPunctuation(char), IsLabel(int) tests.

STYLE: token qualifiers, consistent infinite loop

- move dictionary read implementation out of line,
  in preparation for using dictionary to support
  meta information for an IOobject.