Support backward compatibility with PointElevation filter

Kenneth Morelandrequested to merge
kmorel/vtk-m:pointelev-backward-compat into master

The interface for PointElevation changed the SetLowPoint and SetHighPoint methods to accept a vtkm::Vec3f_64 instead of 3 vtkm::Float64. This means all code using PointElevation wrong.

Why not have both?

Merge request reports