COMP: Fix duplicate member issues.
Make the Implementation member in the vtk::RenderedRepresentation class be private instead of protected.
Addresses the issue reported at: https://open.cdash.org/viewBuildError.php?type=1&buildid=4961725
Make the Implementation member in the vtk::RenderedRepresentation class be private instead of protected.
Addresses the issue reported at: https://open.cdash.org/viewBuildError.php?type=1&buildid=4961725