…#875; closes date-fns#1066)

* Setup Jest
* Update Babel and Power Assert
* Make test karma suite work
* Fix multiple it used instead of describe
* Fix accidentally disabled tests
* Upgrade Sinon
* Add Node.js suite to Travis CI
* Remove node_modules from .flowconfig ignore
* Remove console.log from a test
* Use regexp for exception assertion to make it work in any Node.js
* Disable Sauce Connect because it gives me headaches