Avoids the clutter and maintenance effort associated with providing the
function signature string.

Patch provided by Bruno Santos
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1528

and generate cleaner HTML files.
Thanks to Bruno Santos for various fixes and improvements.
Resolves bug reports:
    http://www.openfoam.org/mantisbt/view.php?id=1516
    http://www.openfoam.org/mantisbt/view.php?id=1016
    http://www.openfoam.org/mantisbt/view.php?id=1512

- a single root entry is interpreted as being the same for all slaves

Problems remain with codedFixedValueFvPatchScalarField:

- readIfModified() notices change on system/codeDict, but the
  codeProperties::setUnmodified() means that only a single entry will
  get processed

- it appears that while dlclose() may (or may not) be actually closing
  the library, there are probably still references about. This means
  that a subsequent reloading still points to the original functions
  and the lookup is not updated correctly.

- new token: token::VERBATIMSTRING
- writing of this type in primitiveEntry
- disabling of all functionEntries in entry