Add .open class to drop down parent (<li>) when it is open. This is nece...

...ssary so the dropdown works properly in a responsive Bootstrap navbar. Without the .open class, the dropdown menu is not rendered properly if the navbar is collapsed.
![screen shot of collapsed navbar showing issue](https://cloud.githubusercontent.com/assets/283872/3137467/e66361f6-e853-11e3-9835-c7de0941135e.png)

![screen shot of collapsed navbar w/fix](https://cloud.githubusercontent.com/assets/283872/3137472/f34ba1ee-e853-11e3-96a3-bff613b1aa53.png)

I'm not sure if this fix is the best approach. In a Bootstrap navbar, the <li> that contains the bs-dropdown element needs the ".open" class applied to it. I felt dirty doing $element.parent().