[WIP][Question] Add travis and test runner

[CristhianMotoche]

Hello!

I like your library as I like habitica. I want to contribute a little bit by solving issues, but first I think adding some tests is worth to avoid breaking the library. I set up Travis for CI and I added mocha as a test runner and talkback to mock the API responses based on VCR's.

Please, let me know what are your thoughts on this. @charlespwd

Cheers!