- sentinel was not working properly when building user-space routines

Eg,
    librunTimePostProcessing.so
    librunTimePostProcessing.so.7 -> librunTimePostProcessing.so.7.1.0
    librunTimePostProcessing.so.7.1.0

- centralize handling of paraview/vtk versioning into wmake/cmakeFunctions

- use "-pvMAJ.MIN" suffix for similarity with the paraview convention

- use sentinel file to ensure clean change of intermediate targets

- ensure all library files are being properly removed

- reported by Bruno

- more consistent with the rest of the OpenFOAM source tree

- improve wmake / wclean behaviour

- although the build is not 100% complete, it is only the run-time
  post-processing with VTK that is affected.

- improve robustness and warning messages

COMP: adjust build order (solvers, utilities)

- as per http://bugs.openfoam.org/view.php?id=2116

- Allows generation of images (currently PNG files) during the run
- ... or afterwards by invoking the execFlowFunctionObjects utility
- Wrapper around VTK functionality
- Support for objects:
  - text
  - points (glyphs: sphere, arrow)
  - lines (tubes)
  - surfaces (wireframe, shaded, combination)
- Colour using:
  - user-defined
  - field values (several colour maps availale)
- For image sequences:
  - dynamic views (camera movement)
  - objects can appear/disappear using opacity
- Building
  - VTK dependency v6+
  - satisfied using ParaView from ThirdParty directory
  - or separate VTK installation