title: How to use success & failure block in SDwebimage
body: <p>I have latest version of <code>SDWebimage</code> but it doesnt have Success &amp; failure
  I tried the following method but <code>SDwebimage</code> doesnt have method </p>
  
  <pre><code>[self.imageView setImageWithURL:[NSURL URLWithString:self.imageURL]
                placeholderImage:[UIImage imageNamed:@"YourPlaceholder.png"]
                         success:^(UIImage *image) {
                             // remove animation
  
                         }
                         failure:^(NSError *error) {
                             NSLog(@"thumbnail error: %@",error);
                             // handle failed download
  
                         }];
  </code></pre>
  
  <p>Does anybody know how to add success &amp; failure block in <code>SDwebimage</code> <code>setImageWithURL</code> or any other alternatife
  I want to handle if there is some error  while getting image from URL</p>