Added recommendation opt-out (bug 1072637)

 ![7d-spxvylir1julp9prgafdcj-sg67frvg75esnapg8](https://cloud.githubusercontent.com/assets/1106/4985733/b7fc5d14-6930-11e4-809f-957cc4093cbf.png)
![screen shot 2014-11-10 at 15 23 23](https://cloud.githubusercontent.com/assets/1106/4985739/c70cb402-6930-11e4-89c7-34c9666b35fc.png)

if you're not going to make this a reusable function, why not just do this:

```js
var showRecs = this.evaluate(function () {
    return document.getElementById('show_recommendations').checked;
});

if (showRecs) {
    this.click('#show_recommendations');
}
```