Don't pass the Search's query_params to #get_solr_response_for_doc_id when getting the featured_item.
Add an autocomplete member resource to the SearchesController.

Move autocomplete json response format into Spotlight::Base.
Merge pull request #652 from sul-dlss/featured-item-scope

Add an autocomplete member resource to the SearchesController.
Merge pull request #651 from sul-dlss/featured-item-params

Don't pass the Search's query_params to #get_solr_response_for_doc_id ...
Don't lookup featured items for searches if the featured_item_id is an empty string or nil.