Edge: make members const
This requires us to eliminate an std::vector:;erase call from Faces.cpp. This in turn can only be done in simple ways if we have rewritten the handling of coinciding vertices, as tested by TruncatedCubeAsBox.
This requires us to eliminate an std::vector:;erase call from Faces.cpp. This in turn can only be done in simple ways if we have rewritten the handling of coinciding vertices, as tested by TruncatedCubeAsBox.