directed-cubical 0.1.2.0

I finally got around to writing some code to output finite directed cubical complexes in VTK format. Initially I was trying to get it to work with the XTK project in hopes of getting some slick WebGL-based presentations, but XTK’s parser for VTK polydata files only supports triangles at the moment (rather than general polygons). I was able to partially work around this by rendering only the triangulations of 2-skeleta, but then XTK only recognized the 2-simplices and not the 1-simplices which were essential to the correct visualization of the corner-reduction algo.

At this point I punted and wrote the code to output files compatible with ParaView (and the specification, of course). ParaView gave me a quick assurance that the bug was with XTK and not me, and then I was able to generate some cool animations.