Adds more filter actions, makes disabled filters all stripey.

In addition to the existing "Remove all" link for the filter bar this adds enable, disable and toggle, and moves them to their own collapsable sub-bar.

It also makes it a bit more obvious when filters are disabled

![image](https://cloud.githubusercontent.com/assets/1250387/4638358/4f63d9f4-53f9-11e4-90f2-86a6495f75f8.png)


Closes #324 
Closes #1582