title: SDWebImage : setImageWithURL fails when used to set image of a UITableViewCell
body: <p>When call setImageWithURL, it fails with following,</p>
  
  <blockquote>
    <p><em>[UIImageView setImageWithURL:placeholderImage:]: unrecognized selector sent to instance 0x149a20 2011-12-14 18:11:38.060 [781:707]
    Terminating app due to uncaught exception
    'NSInvalidArgumentException', reason: '-[UIImageView
    setImageWithURL:placeholderImage:]: unrecognized selector sent to
    instance 0x149a20'</em></p>
  </blockquote>
  
  <p>I can confirm I have included <code>SDWebImage</code> project and required headers correctly as I can use the SDWebImageManager successfully.</p>
  
  <p>Following is the code where I called the UIImageView category method <code>setImageWithURL</code></p>
  
  <pre><code>NSURL* url = [NSURL URLWithString:@"www.abc.com/abc.png"];
  [cell.imageView setImageWithURL:url placeholderImage:[UIImage imageNamed:@"abc.png"]];    
  </code></pre>