- tie the MPI rules to the base compiler type *without* its version.
  Eg, linux64Gcc (which exists) instead of linux64Gcc81

- generalize some of the library extensions (.so vs .dylib).
  Provide as wmake 'sysFunctions'

- added note about unsupported/incomplete system support

- centralize detection of ThirdParty packages into wmake/ subdirectory
  by providing a series of scripts in the spirit of GNU autoconfig.
  For example,

      have_boost, have_readline, have_scotch, ...

  Each of the `have_<package>` scripts will generally provide the
  following type of functions:

      have_<package>          # detection
      no_<package>            # reset
      echo_<package>          # echoing

  and the following type of variables:

      HAVE_<package>          # unset or 'true'
      <package>_ARCH_PATH     # root for <package>
      <package>_INC_DIR       # include directory for <package>
      <package>_LIB_DIR       # library directory for <package>

  This simplifies the calling scripts:

      if have_metis
      then
          wmake metisDecomp
      fi

  As well as reduci...

- this corresponds to what various module or build systems provide.
  ThirdParty builds are unaffected since they install into FOAM_EXT_LIBBIN

- Follow similar pattern as per boost/CGAL with the '*-none' to disable,
  and '*-system' for system installations.

  Also support central non-ThirdParty installations by specifying the
  version as "*-system", but also providing the fully qualified
  *_ARCH_PATH too.

--
ENH: Verify label and scalar sizes used in the metis header.

- ensure they match with expected values, which can be obtained via
  the OpenFOAM definitions for WM_LABEL_SIZE and WM_PRECISION_OPTION

- Only reference the FOAM_EXT_LIBBIN locations when linking.
  The respective SCOTCH_ARCH_PATH/lib, METIS_ARCH_PATH/lib locations
  either do not exist, or are possibly inconsistent and won't be
  seen at run-time anyhow.

- Incorporate decompose/metisDecomp/Allwmake into the top-level
  decompose/Allwmake

Patch contributed by Bruno Santos
Resolves patch request http://bugs.openfoam.org/view.php?id=2212

- drop FOAM_MPI_LIBBIN variable in favour of FOAM_MPI from which
  two different locations can be determined.

  Previously there was something like this:

      FOAM_MPI_LIBBIN = $FOAM_LIBBIN/openmpi-1.5.1

  We now instead determine the locations from the FOAM_MPI directly:

      FOAM_MPI=openmpi-1.5.1

          $FOAM_LIBBIN/$FOAM_MPI     -> OpenFOAM  mpi-related
          $FOAM_EXT_LIBBIN/$FOAM_MPI -> ThirdPary mpi-related

ENH: relocate ParaView libraries and plugins back under FOAM_LIBBIN

- as discussed with Mattijs

- for future updates of scotch, need to edit these two files:

    OpenFOAM-<VERSION>/src/parallel/decompose/Allwmake
    ThirdParty-<VERSION>/Allwmake

- main mplib rules located in GENERAL_RULES with specializations
  (if any) under RULES. Modest change in a few options files, but
  cleans up the rules directories.

  previously in options:
      include $(RULES)/mplib$(WM_MPLIB)

  now in options:
      sinclude $(GENERAL_RULES)/mplib$(WM_MPLIB)
      sinclude $(RULES)/mplib$(WM_MPLIB)

  For GNU make it would be permissible to write both in a single line.

ptscotch - compiles into ptscotchDecomp. All thirdparty decompositionMethods
now moved out of decompositionMethods so add them explicitly to link line
for programs that need them (decomposePar, snappyHexMesh etc.)