Version 0.9.16

The following updates have been made:

• Incorporated the vorder push heuristic suggested by Michael Monagan. As part of this, I’ve added the ability to sort the vertex order according to a depth-first or breadth-first search. Again, this was suggested by Michael and it really makes a big difference for computing Truncated Icosahedron (and probably lots of other graphs). I’ve got to do some more experimentation!