Use Travis CI to ensure package can be built with Python 2.7 and 3.4

[westphahl]

This will use Tox to just build the package and install it for Python 2.7 and 3.4.

Example setup: https://travis-ci.org/westphahl/adafruit-beaglebone-io-python/

[tdicola]

Oh cool, thanks for contributing--that looks like a great idea to get CI going on a lot of the repos. I'm not super familiar with Travis CI but should we do any other setup to have it pointed at the repo and running tests? Thanks for sending over the change!

edit: Ahh, I see more about how to set it up on their site. Thanks for the pointer to it!

[westphahl]

Basically the only thing you have to do is to activate builds for the "adafruit-beaglebone-io-python" repository in your Travis CI settings (https://travis-ci.org/adafruit)

Make sure to activate the "Build pull requests" switch in the repository specific settings in Travis. This will automatically give you a build/install verification for all pull requests that is then shown in the Github UI.