Convert Kabum source to Javascript

The most important features (to me) of coffeescript have made it to recent editions of javascript: list comprehensions, class keyword, arrow functions. I think rather than writing in a different dialect like coffeescript, I'd prefer to use a future version of JS instead. The first pass involves using the compiled JS from the coffee compiler, then I can switch to an ES6 compiler (or use --harmony with Node.js) and convert the code to idiomatic ES6.