More polyhedron facet/vertex extensions

This is a diverse set of pieces geometrically compatible with and extending http://www.thingiverse.com/thing:4934. They are also snap, but not geometrically, compatible with http://www.thingiverse.com/thing:4899 and http://www.thingiverse.com/thing:4893.

I have added spoke versions of squares, pentagons, and hexagons. I have also added version that have both regular and askew polygonal facets. Maybe the straight lines in this version will print more cleanly than the circles in the last version.