refactor BroadcastItemTitleScorer to extract superclass
Extract super-class scorer for Broadcast Items
Add equivalence scorer based on the number of co-ocurring title words
Merge branch 'title-subset-equiv' into stage

* title-subset-equiv:
  Add equivalence scorer based on the number of co-ocurring title words
  Extract super-class scorer for Broadcast Items
  refactor BroadcastItemTitleScorer to extract superclass