Concept for new rev1 node js client

Last night I upgraded the [jsonapi-client](https://github.com/matthewfl/jsonapi-node) that I started a few months ago.  This new version uses getters/setters along with promises to make it feel more like the other clients which are able to make synchronous network calls.

Interacting with this version of the client looks like:
```js
balanced.marketplace.customers.create().add_card(
        balanced.marketplace.cards.create({
            'number': '4111111111111111',
            'expiration_year': '2016',
            'expiration_month': '12'
        })
    ).cards.get(0).debit(500)
     .then(function (debit_obj) { /* everything worked ok */ });
```

Currently everything in the [test](https://github.com/matthewfl/balanced-node/blob/rev1/test/test.js) file works, and the parts that are specific to the resources themselves so far is minimal ([this]( https://github.com/matthewfl/balanced-node/blob/rev1/lib/balanced.js))