Support for body-parser module

I was having some trouble getting the data to come through using the new express and bodyParser style.

example:

```js
var express = require('express');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.json());
app.use(cgh(..));
```
Merge pull request #4 from nnnnathann/master

Support for body-parser module (req.body)