title: unable to set custom font in NSMutableAttributedString
body: <p>I am unable to set custom font in <code>NSMutableAttributedString</code></p>
  
  <p>But when setting font to System it's working fine.
  Here is my code:</p>
  
  <pre><code> NSString *str=@"my attributed text";
      NSMutableAttributedString *attString=[[NSMutableAttributedString alloc] initWithString:str];
      UIFont *customFont =[UIFont fontWithName:@"Play-Regular" size:13.0];
      [attString addAttributes:@{
                                 NSForegroundColorAttributeName: [UIColor colorWithRed:111.0/255.0 green:75.0/255.0 blue:26.0/255.0 alpha:1.0],
                                 NSFontAttributeName: customFont,
                                 } range:NSMakeRange(0,str.length)];
  </code></pre>
  
  <p>I am unable to set custom font in UISearchbar.</p>
  
  <pre><code>[[UITextField appearanceWhenContainedIn: [UISearchBar class], nil] setDefaultTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor], NSFontAttributeName:[UIFont fontWithName:@"Play-Regular" size:13.0]}];
  </code></pre>
  
  <p>Although I have successfully added Play font.</p>
  
  <p>But it working fine when setting </p>
  
  <pre><code>[[UITextField appearanceWhenContainedIn: [UISearchBar class], nil] setDefaultTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor], NSFontAttributeName:[UIFont systemFontOfSize:13.0]}];
  </code></pre>