Single-valued Tag inputs don't save their values

(Bug, Closed -> Fixed, Priority: Critical, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor, Tag Sets
Summary: If you define an ExactlyOne or Optional Tag, it looks like it works correctly, but it never actually saves.
The issue is that we're never firing the "change" event on the text field, so it's never being saved. Easy to fix.
Don't know when this broke, but it was probably quite a while ago -- shows how rarely I use single-value Tags.