CoffeeScript support

Hi,

Thanks for this awesome project. I have a quick question, i've been playing with `astexplorer` to add coffee-script support and i managed to get both [coffee-script](http://coffeescript.org/) and [decaffeinate](https://github.com/decaffeinate/decaffeinate) parser working with `astexplorer`.

There is one thing i am not sure if it's right: I am using `wzrd.in` (browserify as a service) to load these parsers using `scriptjs` as I couldn't get them working with webpack via regular import/require.

Before trying to submit a PR, I wanted to ask (1) is `coffee-script` support considerable for `astexplorer` (2) is it ok to fetch parser scripts from other resources (3) if not what would be the correct way to implement this? (I tried to add folders under `packages` folder, but no luck)