Integrate previous work on haystack/elasticsearch into current search/explore UI
Adjust boost values for title, abstract
Remove 'iid' or rename to 'id', tweak search_indexes
Merge remote-tracking branch 'origin/master' into haystack2
Make haystack/elasticsearch optional
Redirect search API calls to Haystack if activated
Merge pull request #1423 from mbertrand/haystack2

Integrate previous work on haystack/elasticsearch