Show users how fulltext search queries are parsed and executed; don't query stopwords or short tokens
This shows users a readout of which terms were actually searched for.
This also drops those terms from the query we submit to the backend, dodging the weird behaviors / search engine bugs in T12137.
This might need some design tweaking.
Reviewed By: chad
Differential Revision: https://secure.phabricator.com/D17672