allow to hide scores

* new (optional) config option in KWS: show_scores. fixes issue #81
* by default scores are hidden
Merge pull request #4044 from vidma/kwd-search-no-autocompl-fix-ranking

allow to hide scores
Add debuging output
Remove obsolete call to check_services
Remove similar_queries; replace get_records with col.find call to avoid transient DAS misbehavior under high load