Merge topic 'remove_deprecated_7.0'

74540cc3 Remove related legacy code in vtkSmartVolumeMapper
8de89d86 Remove deprecated methods in vtkSmartVolumeMapper
7e830ca4 Remove deprecated classes in Rendering/VolumeOpenGL
88f3181b Remove doc reference in vtkAMRVolumeMapper to removed classes
7d947aa5 Update examples to use newer classes
11d2f5d3 Remove references to deprecated classes in XML files
89244825 Remove Rendering/Volume/Testing/Tcl/gaussian.tcl
e329fc55 Remove Rendering/Volume/Testing/Cxx/volProt.cxx
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !3344