Improved search results filter dropdown

## Current

Currently filter dropdowns on search results page can be **very** long and off the page

![Screen_Shot_2016-03-11_at_15.25.24](/uploads/3418b0a6f4f8a0a8bd2441b53502c574/Screen_Shot_2016-03-11_at_15.25.24.png)

## New

Changed over to the new dropdown

![Screen_Shot_2016-03-11_at_15.29.06](/uploads/2d3a4a9b3e50f3e0fc1748a026cd5905/Screen_Shot_2016-03-11_at_15.29.06.png)

See merge request !3183