title: SlickNav jQuery plugin - only one open menu
body: <p>I would like to achieve an accordion effect with this plugin. By default it works as a toggle. I would need to collapse opened menus when I click on another level 1 menu. </p>
  
  <p>My structure is: </p>
  
  <ul>
  <li>level 1 anchor</li>
  <li><p>level 1 anchor</p>
  
  <ul>
  <li>level 2 anchor
  <ul>
  <li>level 3 anchor</li>
  <li>level 3 anchor</li>
  <li>level 3 anchor</li>
  </ul></li>
  <li>level 2 anchor</li>
  </ul></li>
  <li><p>level 1 anchor</p></li>
  <li>level 1 anchor</li>
  </ul>
  
  <p>I need to close all opened level 1 submenus when I click on another submenu. 
  Could anyone help me with this please? </p>
  
  <p>Thank you very much. </p>
  
  <p>I'm using this plugin - <a href="https://raw.github.com/ComputerWolf/SlickNav/master/jquery.slicknav.js" rel="nofollow">https://raw.github.com/ComputerWolf/SlickNav/master/jquery.slicknav.js</a></p>
  
  <p><a href="http://slicknav.com/" rel="nofollow">http://slicknav.com/</a></p>