Discrepant with qs.parse passing an object

``` js
var qs = require('qs');
var qsparser = require('querystringparser');

console.log(qs.parse({
    key: 'Value & value',
}));

console.log(qsparser.parse({
    key: 'Value & value',
}));
```

``` js
{ key: 'Value & value' }
{ key: 'Value ', ' value': '' }
```

Passing an object to `qs.parse` however is not documented, but probably should have been since exposed.
