ENH: make it easier to switch between the various make dependencies programs.

- However, the new ragel-based parser is much faster
  than the others, and does not cause 'too many open files' error
  that the flex-based parser does (issue #784).

  The timings (using src/sampling as being somewhat representative)

    $ wclean; wmakeLnInclude -u .; time wmake -s dep

        3.4s  wmkdepend (ragel) [now default]
        5.7s  wmkdep (flex)
        6.1s  cpp -M

- The makeDepend script is for testing purposes only, but could used as
  a hook for other dependency generation systems (eg, ninja).
  It simply wraps 'cpp -M' in a form that is calling compatible with
  wmkdepend.

BUG: wmkdepend parser was missing optional leading space on #include match

STYLE: use -G2 (goto-based) option for wmkdepend state machine

- the machine is compact with few states and lends itself to this

wmake/scripts/cmakeFunctions

@@ -6,20 +6,8 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM.
-#
-#     OpenFOAM is free software: you can redistribute it and/or modify it
-#     under the terms of the GNU General Public License as published by
-#     the Free Software Foundation, either version 3 of the License, or
-#     (at your option) any later version.
-#
-#     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-#     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-#     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-#     for more details.
-#
-#     You should have received a copy of the GNU General Public License
-#     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, licensed under GNU General Public License
+#     <http://www.gnu.org/licenses/>.
 #
 # Script
 #     cmakeFunctions