first commit after merging dfs and bfs
breadth first completed, with tests.
working on main, something wonky going on
fixed breadth first to not leave traces, added main to demonstrate both traversals
Fixed a bug where a DF traversal test fixture was cyclc when it should have been acyclic, and also fixed related unit tests. Also fixed a bug where the DF traversal method couldn't be run a second time on the same graph. Added another unit test to ensure multiple runs of the DF traversal return the same result.
Added requirements.txt and .travis.yml for Travis CI integration
Merge branch 'master' of https://github.com/sazlin/data-structures