title: change switch position behavior
body: <p>How to change switch behavior in sortable? I mean by default there <code>1 - 2  - 3 - 4</code>
  <a href="http://jsfiddle.net/keGuN/" rel="nofollow">http://jsfiddle.net/keGuN/</a>
  when I switch positions of <code>4</code> and <code>1</code> - they transform into <code>4 - 1 - 2 - 3</code>. 
  I want only switch positions of <code>4</code> and <code>1</code>(<code>4 - 2 - 3 - 1</code>). How to do it?</p>