Caching recent searches for autocomplete

Added new panel at autocomplete with recent searches, minlength for
autocomplete changed to 0, but will do request to database only if 2+
chars in string. also did little changes at jquery.tagsinput
I know that it isn't really that important here. It's more of a stylistic choice, `?` exists in coffeescript for this reason, so why not use it? It makes the code more readable.