title: Remove UIColor CGColor - KVC warning
body: <p>How to remove <code>[[UIColor grayColor] CGColor]</code> stupid warning?</p>
  
  <pre><code>[self setValue:
       [[UIColor grayColor] CGColor] 
            forKeyPath:[NSString stringWithFormat:@"_View_%@%d.layer.borderColor", 
                i&gt;=10?@"":@"0", i]];
  </code></pre>
  
  <blockquote>
    <p>Incompatible pointer types sending 'CGColorRef' (aka 'struct
    CGColor *') to parameter of type 'id'</p>
  </blockquote>
  
  <p>thanks.</p>