title: jQuery: Remove class if other element is clicked
body: <p>I have an ul-list that contains li-elements. When the user clicks on one of these li elements a class should be added to that element. </p>
  
  <p>This is easy to setup, however, when the other li-element is clicked I want the "active"-class to be removed from the non-active li.</p>
  
  <p>I have made a jsfiddle of the problem:
  <a href="http://jsfiddle.net/tGW3D/" rel="noreferrer">http://jsfiddle.net/tGW3D/</a></p>
  
  <p>There should be one li-element that is red at any one time. If you click the second and then the first, only the first should be red.</p>