Contour Filter
The MarchingCubes worklet is extended to work with all 3D cell types supported by VTKm. It is the same "marching cubes" algorithm but driven by tables with entries for each cell shapes. Correctness is visually verified with a isosurface of a clipped Tangle field. Most instances of reference to "MarchingCubes" is renamed to "Contour".
Edited by Li-Ta Lo