2D/Belyi_Torus: useless option -c
2D/Belyi_Torus: use Constellation1 for display
libvb/Constellation1: leave less cruft on the screen
libvb/math: implement Klein's J invariant
libvb/Belyi_Torus: less automatic finding, refine as needed
libvb/Constellation1: saner display
2D/Belyi_Torus: filter by maximal degree
libvb/Constellation1: precomputation was a bad idea here
libvb/Bitmap: reimplement tessel using a lambda, and use it
2D/Bitmap: get rid of the old compute/tessel pair