Maintain cache/localStorage of keywords for a shadow autocomplete

[peterdotjs]

User feedback: "I love Quick Find, but it would be great to have a default search phrase or have it such that the phrase gets remembered from instance to instance so as not to necessitate re-typing a term when loading up a new page."

Won't be able to have 2 autocomplete menus - just have grey/shadow showing most searched keyword based on user input.