vtkNew and vtkSmartPointer

[amaclean (Andrew Maclean)]

@allison.vacanti

IMO they’re both still useful to have because of convention – vtkNew means “I own this pointer, which must remain the same for my lifetime”, vtkSmartPointer means “I use this pointer, which came from somewhere else and might change,” which is useful to know at a glance when maintaining code.

I like this comment, this is what I mean about clarifying the roles of vtkNew and vtkSmartPointer.