Adding cycle tests for undirected graphs.

Previously test_cyclic_by_dfs only worked for directed tests. This commit adds
cycle tests for undirected graphs. This requires the addition of a colormap
for graph edges.
Moving init of graph search colormaps to param lists.

Colormaps for depth-first and breadth-first searches will now be initialized
in the parameter lists of the graph_traversal functions instead of being
initialized conditionally equaling "nothing".
Merge pull request #43 from mweiden/undirected-cycletest

Adding cycle tests for undirected graphs.