title: UITextField check empty after editing
body: <p>So I have next problem <a href="https://stackoverflow.com/questions/16396795/uitextfield-strange-behavior-when-delete-symbol-in-first-time">UITextField strange behavior when delete symbol in first time</a> and I see next decision: check after first editing textfield text and replace it if empty. How can I check it, no one delegate method cann't help me</p>