Previously format-graph-from-roots would crash if given a :duplicate-test argument that wasn't one of the equality predicates accepted by make-hash-table.

Previously format-graph-from-roots would crash if asked to format a :dag. This is fixed. Sorta. I'm not bragging about the dag layout method --- it really needs a nice layering, but doesn't have one yet. But I hope it's better than crashing! Note that it will /still/ crash if asked to format a general :digraph.

When I was testing this, I discovered that FORMAT-GRAPH-FROM-ROOT, the singleton wrapper, wasn't exported from the CLIM package. Since it's required by the spec, I added the export, and committed package.lisp.

My first commit. Hope I haven't gaffed anything! Seems like the clim-listener still works, and that's really my only test case...

Cheers, R