Merge topic 'fix_ogg_support' into pv-master

227749c Cleanup OggTheora support.
Merge topic 'fix-image-append' into pv-master

710ce99 BUG #14086: Fix vtkImageAppend when no active scalars are present.
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

* pvvtk/pv-master:

Change-Id: I7f71aa9bb43a83428d5addca276a73e48d40f840