Joyride: honor configuration options by calling #events rather than #init so that non-default options aren't wiped

Custom Joyride options that are properly specified, e.g.

```javascript
$(document).foundation('joyride', 'start', {
    cookieMonster: true,
    cookieExpires: 600,
    cookieName: 'tour'
});
```

Weren't getting honored. This is because Joyride's #start method calls #init rather than #events--making an unnecessary call to #init that wipes out the custom options.