The reason for unattaching media instead of removing it is to support
delete & redraft functionality, but remote or staff-removed statuses
will never be redrafted, so the media should be deleted immediately
* Add more accurate hashtag search
Using ElasticSearch to index hashtags with edge n-grams and score
them by usage within the last 7 days since last activity. Only
hashtags that have been reviewed and are listable can appear in
searches, unless they match the query exactly
* Fix search analyzer dropping non-ascii characters
* Change hashtag search to only return results that have trended in the past
A way to eliminate typos and other one-off "junk" results
* Fix excluding exact matches that don't have a score
* Fix tests
Eugen Rochko
Yusuke Nakamura