Graph properties for the attached graph doesn't come back.

[jdramsey]

native_smooth_clean_master_graph.txt

The problem is the cycle checker. It checks for each node, depth first, whether there is a path from that node to itself. The question is whether there's a better way. Perhaps breadth first?

[jdramsey]

There is a breadth first path checker in GraphUtils; it was not however configured to find cyclic paths. Reconfigured it. Now the distinction between cyclic and acyclic graphs can be scaled up for EdgeListGraph. That is, if the existsDirectedCycle() method is called on an EdgeListGraph, it will quickly distinguish cyclic from acyclic graphs.

This solution needs to be copied to other graph classes. Also, the example cyclic path may need to be commented out for now, since it's going to have the same problem as the depth first cycle checker.

[jdramsey]

The latest commit fixes #17, though for now at least I've commented out the "example cycle" line in the graph properties dialog, since it has the same problem as the depth-first cycle checker did. Maybe at some point a breadth-first algorithm can be written to recover an example cycle quickly from a graph.