title: UIButton -setTitle: forState: doesn't seem to work
body: <p>I'm trying to dynamically update the title of an <code>IBOutletCollection</code> of <code>UIButton</code>s. I expect the title to be set to</p>
  
  <ul>
  <li>the letter 'S' when selected and</li>
  <li>the text "D|S" when disabled and selected.</li>
  </ul>
  
  <p>It wasn't working, so I printed out the <code>titleForState:</code>s and it looks like the title is not getting set properly. Am I using <code>setTitle: forState:</code> correctly?</p>
  
  <pre><code>@property (strong, nonatomic) IBOutletCollection(UIButton) NSArray *buttons;
  ...
  - (void)updateUI  // Calling this from IBAction
  {
      for(UIButton *button in self.buttons) {
          [button setTitle:@"S" forState:UIControlStateSelected];
          [button setTitle:@"D|S" forState:UIControlStateSelected|UIControlStateDisabled];
  
          NSLog(@"%@ %@ %@ %@ %d %d",
                [button titleForState:UIControlStateSelected],
                [button titleForState:UIControlStateSelected],
                [button titleForState:UIControlStateNormal],
                [button titleForState:UIControlStateSelected|UIControlStateDisabled],
                button.selected,
                button.enabled);
      }
  }
  </code></pre>
  
  <p>Here's the console output:</p>
  
  <pre><code>2013-02-21 21:05:36.070 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.072 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.073 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.073 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.073 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.074 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.074 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.074 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.075 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.075 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.076 Buttons[37130:c07] D|S D|S   0 1
  2013-02-21 21:05:36.076 Buttons[37130:c07] D|S D|S   0 1
  </code></pre>