title: Bold a part of title, iOS 7
body: <p>I have read several method about bolding a part of string.
  But I still can't get it work.</p>
  
  <p>Here's my code</p>
  
  <pre><code>#define FONT_OPEN_BOLD(s) [UIFont fontWithName:@"OpenSans-Bold" size:s]
  </code></pre>
  
  <p>In viewDidLoad function</p>
  
  <pre><code>NSString *stringName = @"ShowTimes" ;                     
  UIFont *font = FONT_OPEN_BOLD(15.0f);
  NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc] initWithString:stringName];
  [attrString addAttribute:NSFontAttributeName value:font range:NSMakeRange(0, 4)];
  
  self.title = stringName;
  </code></pre>
  
  <p>Any suggestion? 
  Thank you in advance. ^^</p>