Refactor Result Set Presenter and Finder

With the new sentence generation by fragment,
finder#facet_sentence_fragments returns an array containing all the
fragments which is then joined together by result_set_presenter.
Also with the link to the Finder without that filter applied, we now
use the other_params portion of the sentence fragment.
Add Date Facet sentence fragment and spec

Also refactor the view to not break when there's no value present.