Unhide the unit_tests.rb file.

There's already a tests/config.rb file, so I don't quite understand the rationale for making ".unit_tests.rb" a dot file that is hidden by default in some OSes.

I went ahead and made this unhidden in my copies of the navigator files in my projects.

Actually, I moved everything but the .travis.yml file into the tests/ directory so that my project root was cleaner. I'm not sure if you are interested in that big of a change, but I can do a pull request if you are.

Keep up the awesomeness!