title: Removing the title text of an iOS UIBarButtonItem
body: <p>What I wanted to do is to remove the text from the 'Back' button of a <code>UIBarButtonItem</code>, leaving only the blue chevron on the navigation bar. Keep in mind that I'm developing for iOS 7. I've tried several methods, including, but not limited to:</p>
  
  <p>This is the image method which I did not like (the image looked out of place):</p>
  
  <pre><code>UIBarButtonItem *barBtnItem = [[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"iOS7BackButton"] style:UIBarButtonItemStylePlain target:self action:@selector(goToPrevious:)];
  self.navigationItem.leftBarButtonItem = barBtnItem;
  </code></pre>
  
  <p>Another method I tried was this, which simply did not work (nothing was displayed):</p>
  
  <pre><code>UIBarButtonItem *barBtn = [[UIBarButtonItem alloc]init];
  barBtn.title=@"";
  self.navigationItem.leftBarButtonItem=barBtn;
  </code></pre>
  
  <p>What I wanted to achieve is something like the back buttons found in the iOS 7 Music app, which only featured a single chevron. </p>
  
  <p>Thanks.</p>