Perf and filter fixes

I identified two problems with the recent commits:

* The filters stuff is entirely broken. A fast fix was easy.
* The perf issue I already commented on regarding ng-switch vs collapse. I coded up some (somewhat hacky) way to preserve the animation while still using ng-switch. Maybe in the long term it would be better to properly implement the `enter`/`leave` angular "events" for ng-switch instead of using bootstrap collapse.