title: remove "one" action from multi actions in target-action UIbutton
body: <pre><code>[_btt1 addTarget:self action:@selector(clicked:) forControlEvents:UIControlEventTouchUpInside];
  [_btt1 addTarget:self action:@selector(clicked2:) forControlEvents:UIControlEventTouchUpInside];
  </code></pre>
  
  <p>There are 2 actions in _btt1.</p>
  
  <pre><code>2013-05-31 10:33:31.300 testTargetAndSelector[6029:c07] actions : (
      "clicked:",
      "clicked2:"
  )
  </code></pre>
  
  <p>I remove clicked2 action like this.</p>
  
  <pre><code>[_btt1 removeTarget:self action:@selector(clicked2:) forControlEvents:UIControlEventTouchUpInside];
  </code></pre>
  
  <p>but there is no action in _btt1.</p>
  
  <pre><code>2013-05-31 10:33:32.731 testTargetAndSelector[6029:c07] actions : (null)
  </code></pre>
  
  <p>How can I remove single action from multi Actions?</p>