Pass along ajax details in `sync`

Everyone wins this way...

```js
model.fetch({
  success: function (model, resp, options) {
    options.textStatus; // win
  },
  error: function (model, xhr, options) {
    options.textStatus; // win
    options.errorThrown; // win
  }
});
```

/cc @tgriesser @braddunbar @jashkenas

Reference: http://api.jquery.com/jQuery.ajax/