change svg to png
Use clearer variable names

Replace `r` with `result`, and use the `params` hash instead of
assigning request.query_parameters to `qp`, to comply with the style
guide and be more readable.  Use @search_term in search_params hash
instead of params[:q], to reduce duplication of the parameter name
holding the search string.
switched to background images
Merge pull request #541 from alphagov/performance-platform-png

change svg to png
Extract search #index action to a presenter
Extract search #unified action to a presenter
Merge pull request #551 from alphagov/unified_search_frontend

Unified search frontend

https://www.pivotaltracker.com/story/show/65973218
WIP patch to display the organisation facets in search results