Implement flying edges for rectilinear and curvilinear data

The current implementation of flying edges only works on uniform grids (that is, data sets with CellSetStructured<3> cell sets and ArrayHandleUniformPointCoordinates coordinates systems.

The basic idea of the algorithm only relies on the cell set structure (i.e., CellSetStructured<3>), not so much on the point coordinates. However, there is an optimization in the implementation (in worklet 4 if I remember correctly) that produces output coordinates much faster based on uniform spacing. This optimization is important (it's used a lot). However, data sets with other point coordinates fall back to marching cells, which is significantly slower. There should be an alternate code path that does flying edges that interpolates coordinates like any other field.

I suggest doing this after #773 (closed).