Merge topic 'fix_extract_cth_filter' into pv-master

323ad38 Refactor vtkExtractCTHPart.
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

* pvvtk/pv-master:

Change-Id: I271c5734bb0b1b95c266c6c1fe1f61f9805b3eb3