ENH: extended runTimePostProcessing (#1206)

- Extended runTimePostProcessing to include access to "live"
  simulation objects such a geometry patches and sampled surfaces
  stored on the "functionObjectObjects" registry.

- Add 'live' runTimePostProcessing of cloud data.
  Extracts position and fields from the cloud via its objectRegistry writer

- For the "live" simulation objects, there are two new volume filters
  that work directly with the OpenFOAM volume fields:
      * iso-surface
      * cutting planes
  Both use the VTK algorithms directly and support multiple values.
  Eg, can make multiple iso-levels or multiple planes parallel to each
  other.

- When VTK has been compiled with MPI-support, parallel rendering will
  be used.

- Additional title text properties (shadow, italic etc)

- Simplified handling of scalar-bar and visibility switches