Set up Travis CI

[anniejw6]

http://juliasilge.com/blog/Beginners-Guide-to-Travis/

Have testing, want automated testing...

[anniejw6]

Once #49 #48 #45 and #47 are merged, I think travis won't actually error out... yay

[nathanielolin]

Think you get to close this!

[anniejw6]

Closed with #24