ENH: Changes required by ParaView 10/11/2017
- Needed to replace QVTKWidget with QVTKOpenGLWidget
- vtkInstantiator is also depricated and there is no replacement
The classes deleted where not being used by anyone.
Also vtkMultiBlockWrapper has had most of its internals deleted - as of now it used mainly a way of using consistant field/cell data array names