Add 'kwicks-collapsed' class on collapsed elements

By adding **.kwicks-collapsed** class to collapsed elements when another element is expanded/selected you can make nice behavior like:

![image](https://f.cloud.github.com/assets/1493738/815587/33ca1cfe-ef2c-11e2-8326-cf19b6a549ee.png)
![image](https://f.cloud.github.com/assets/1493738/815593/503447fc-ef2c-11e2-9987-dcd259c98418.png)
![image](https://f.cloud.github.com/assets/1493738/815560/a38b55fe-ef2b-11e2-8458-85710e7a3f70.png)
![image](https://f.cloud.github.com/assets/1493738/815596/63e226ac-ef2c-11e2-9c7e-dcc4a9a10009.png)

The **active-collapsed-classes.html** shows an example of what you could do with some CSS.