Filter mappings by path, new URL, tag, and type

* Show a selection of menus beneath a count of mappings
* Click menus to reveal quick filter options
* Filters always add to existing filters
* Includes a quick option to remove a set of filters or all filters
* Allow filtering by path and new URL in combination
* Introduce filtering by type, and link to filtered views from dashboard
* For non-javascript users include a page with a filter form

![screen shot 2014-02-28 at 14 31 41](https://f.cloud.github.com/assets/319055/2310414/1df6da32-a2e3-11e3-8373-d76b99d4f0f9.png)