Added a search results page.

The typeahead autocomplete only completes characters in an organization's
name and a person's full name. Now a final result called 'Search the
website for "<your query>"' is on there as well, and it links to a
search results page that searches the database more
thoroughly--specifically,through organization mission, user bio and
title.
Turn the search field into an actual form.

This only seems to do anything on systems with JS disabled, though, as
typeahead.js seems to prevent users from submitting the form via
pressing enter. Perhaps it works on mobile devices, though?