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
My only concern with 0.4 is that disabled filters become hard to read:

![screen shot 2014-10-15 at 11 17 09 am](https://cloud.githubusercontent.com/assets/1250387/4650933/aac8ff74-5497-11e4-82d6-4ba814424ace.png) ![screen shot 2014-10-15 at 11 17 50 am](https://cloud.githubusercontent.com/assets/1250387/4650934/b056a8f6-5497-11e4-8a94-6b4fa05057b1.png)

Though now that I look at them side by side, maybe not that bad?