Allow multiple output types

Hello! I am super excited to start using CoffeeScriptRedux, particularly for source maps.

While implementing it, though, I started to notice some pretty big limitations of the cli (e.g. single output at a time) and the arguments handling (e.g. --output sometimes ignored). 

I've started a set of modifications that will allow us to now generate multiple output types during a single run on a file. One major benefit this opened the door for is, when writing `js` and `source-map` output, the two are now linked with the proper comments.

This is not yet 100% complete, but it is far enough along that it is working quite well for my team - so I thought it best to start getting your thoughts and input too. I hope to wrap it up over this weekend or early next week.

Here is an example of how we are using it now:

```
$ coffee -i 'path/to/public/file.coffee' --js 'path/to/public/file.js' \
          --source-map 'path/to/public/file.js.map'
```

I hope that this approach fits well into your vision for CoffeeScriptRedux. Let's talk!