add shortkeys to toggle the search engine (bug 200884), by using ctrl-arrow up and down in the search bar.
remove the pref browser.search.defaultengine. Now we rely on the local store so we can have several windows with different search engines.
git-svn-id: svn://10.0.0.236/trunk@190431 18797224-902f-48f8-a5cc-f745e15eee43