First Stable Revision.

This adds the first stable revision of Exercism exercises in ECMAScript 6. The initial contributed exercise is `palindrome-products`. It was an exercise that was involved enough to warrant some ES6 features, but easy enough to digest that we were not biting off too much (given ES6 is so new).

Since ES6 isn't fully supported in node yet; we are transpiling ES6 syntax to ES5 using [traceur-compiler](https://code.google.com/p/traceur-compiler).

We are also [adding node_modules to the repo](http://www.letscodejavascript.com/v3/blog/2014/03/the_npm_debacle) for stability, speed, and simplicity. Upon cloning the repo, one should only have to type `make` to get going.