title: TinyMCE link button & popup: get rid of items in class dropdown list
body: <p>In TinyMCE, when a user clicks the link button, a popup window appears prompting for link information. One of the fields in this popup is for css "Class". </p>
  
  <p>How can you clear this list? I saw there is a plugin setting for the advlink which allows you to provide a list of css classes, but I don't want to use advlink as I don't want the popup and other tabs in the link window.</p>