define a specific animation for an alert-box

Use another animation than the default *fadeOut*. It can be defined during the initialization:
```
$(document).foundation('alerts', {animation: "slideUp"});
```
or at the element level:
```
<div data-alert class="alert-box" data-options="animation:slideUp">
  This is a notification.
  <a href="#" class="close">&times;</a>
</div>
```
I'm using data-options, I'm not sure what is the convention: data-options or data-animation in this case ?