title: Camera.autoFocus(myAutoFocusCallback) doesn't work
body: <p>I have a problem with the android autoFocus() function.
  I just want my App to auto focus when taking a picture.</p>
  
  <pre><code>camera.autoFocus(myAutoFocusCallback); 
  </code></pre>
  
  <p>doesn't work at all.
  Log.i(MainActivity.TAG, params.getFocusMode()); prints ' auto '.
  My Camera does support autofocus^^</p>