Add a startOpen option to the SlideOut Tab so tab will start open.

Setting startOpen: true in the data-wet-boew will have the slide out tab default to open when the page loads. 
Basically it runs the toggle function once the tab is finished loading. Having it slide open reinforces to the user that this they can toggle this functionality.

To add this functionality add the following to the data-wet-boew attribute

    data-wet-boew='{startOpen: true}'

It defaults to closed if no attribute is set.



This is for issue #1064

/cc @berubs @pierreliz