Merge topic 'update_vtk_sha1' into pv-master

118242d9 Merge topic 'tiff-zeiss' into master
c28d5026 Merge topic 'ExposeSlabSum' into master
048419fb Add SetSlabModeToSum() to vtkImageResliceMapper.
8dc4fbe9 Merge topic 'CleanHyperTreeGrid' into master
07512db9 Merge topic 'nifti' into master
e7aa61da Add reader/writer for NIFTIv1 and NIFTIv2 files.
c13f410a Merge topic 'RestoreInteractionWidgetTests' into master
1098bc2e Merge topic 'fix-locator-recreation' into master
7ff8bfd0 Two fixes for certain lsm (zeiss) tiff images.
33916af1 Merge topic 'tiled-tiff-extent' into master
0fe573e8 Fix the extent for tiled tiff files.
eb1a585d ENH: Provide PlaybackFile for recorded interaction events
f82238ed PERF: Parallel streamline was slow. Fixed.
f183298c Merge topic 'python-ptr-erase' into master
666ec458 Merge topic 'vtkweb_ssl' into master
d47d6677 Merge topic 'catalyst-web-better-workflow' into master
...
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

* pvvtk/pv-master:

Change-Id: Ie60bd383aa22b225de246e543369e876095a23c6