Add travis ci support

This should help prevent issues like #25, #26 (via #20) in the future.  [Here](https://travis-ci.org/andrewcohen/viper/builds/40928558) is a sample build from my fork (with #25 merged in. The build for this PR will fail because it doesn't contain #25) 

@spf13 - You'll have to flip the switch [here](https://travis-ci.org/profile/spf13) to enable builds