title: SDWebImage setImageWithURL iOS8 crash
body: <p>I've been using SDWebImage successfully for long. But with iOS8 its crashing when we set image i.e.</p>
  
  <pre><code>[ myImageView setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@",@"url"]] placeholderImage:[UIImage imageNamed:PROFILE_HOLDER_IMAGE]];
  </code></pre>
  
  <p>Is there way to avoid it</p>
  
  <p>Cheers</p>