title: Use jQuery to get a list of classes
body: <p>I have a un-ordered (<code>ul</code>) HTML list. Each <code>li</code> item has 1 or more classes attached to it.
  I want to go through this <code>ul</code> list and get all the (distinct) classes. Then from this list create a list of checkboxes whose value matches that of the class and also whose label matches that of the class.  One checkbox for each class.</p>
  
  <p>What is the best way to do this using jQuery?</p>