title: merged months in datepicker
body: <p>Using jquery ui datepicker,</p>
  
  <ol>
  <li>Can I display and merge two months together?</li>
  <li>Can I set the months sliding top(backward)-down(forward)?</li>
  </ol>
  
  <p>This an example of what I need:</p>
  
  <p><img src="https://i.stack.imgur.com/pQBsN.png" alt="enter image description here"></p>