4024 Associate labels and autocomplete fields

https://code.google.com/p/otwarchive/issues/detail?id=4024

Because the autocomplete plugin keeps the old input, hides it, and adds a new input to work its magic, any field that provided autocomplete options was going unlabeled for screen readers. What I've done here is modify it to take the id off the original, now-hidden input and put it on the new input, so now `<label for="field_id">` will find the input it's looking for.

I've also minified the autocomplete JavaScript file.

(This was annoying me for ages, and I have no idea why I didn't think of this solution until now.)