Ty work

Created a lot more tests for ReverseGraph. Made tests to check the directedness of a reverse graph with 1 node, 5 nodes, and 10000 nodes.
hmm...does this test pass right now? i would not expect that. the graph is directed, so it should have no edges. the difference between arcfilter.all and arcfilter.edge is that arcfilter.edge only returns undirected arcs.