Convert to ES6 (Babel me)

[nmccready]

For main code not specs.

Reasoning:

• get more contributors (As much as I love CoffeeScript repo contributors are always low due to it)
• CoffeeScript (Jeremy's) appears to have no path forward for ES6, Coffee2 (Wrath of Khan seems dead)
• babel and ES6 is the new hotness and I am tired of fighting it.

https://www.google.com/trends/explore#q=coffeescript%2C%20jsx%20react%2C%20babeljs%2C%20es6%2C%20%2Fm%2F0n50hxv&cmpt=q&tz=Etc%2FGMT%2B4