Add tests and update some metadata

[dblessing]

Are you open to adding automated testing via Travis? This includes some minor changes so the project can have run on Travis. I added only Ruby versions 2.2 and 2.3 because the dependencies don't install cleanly on older versions. If there is a better matrix, please let me know.

This also removed the ruby-debug19 dependency because it's really old and I couldn't even get it installed on my workstation with Ruby 2.3.1. If there is a reason why we need it, we can see how we can include it in a way that installs easily on both dev workstations and Travis.

Finally, it adds the Gemfile.lock, because this should be committed instead of ignored.

Thanks for considering adding this to your repo. Please enable the main repo in Travis before merging this.

[dblessing]

@miketierney Will you please review this PR when you have a moment?