filter: Filter 2.0 — greater extensibility

This patch rebases filters into a row-based layout and redesigns the filter apply method to be more extensible. It also redesigns the UI to be more dynamic and to allow for actions to be added without database modification and actions can also have complex configurations.

##### Simpler view — only show configured actions
![screen shot 2014-09-30 at 11 08 55 pm](https://cloud.githubusercontent.com/assets/672074/4470163/ca9ae16e-4920-11e4-9aea-5319a4925fb8.png)

##### Add new action from drop down
![screen shot 2014-09-30 at 11 09 12 pm](https://cloud.githubusercontent.com/assets/672074/4470171/e07017ac-4920-11e4-87bf-3ab6ebb96a83.png)

what was the meaning of the `ext_id` column?