Cannot toggle animation in libigl viewer

[aiwen324]

Other keys function as expected, only nothing happens while press 'A'

[abhimadan]

We aren't marking you on whether or not the animations work (and I believe that we didn't set those up to work either), so if you don't see any mismatches between your brute force and tree outputs, and if your intersections code in the libigl viewer looks like it's highlighting actual intersections, you should be fine.