fixed the callback functions, reorganized the demos into variation sets

added a demo "variation" that uses all of the callback functions.

each callback:
 * inspects the $table
 * passes the row order in a server request
    - querystring parameter format is that of a PHP array:
        ?id[]=1&id[]=2&id[]=3
    - the back-end script:
        http://isocra.com/articles/ajaxTest.php
        http://isocra.com/articles/ajaxTest_php.html
      is actually leveraging the one used at:
        http://isocra.com/2008/02/table-drag-and-drop-jquery-plugin/#3.1
      which is a jquery plugin that:
       * is functionally similar to this project
       * is completely unrelated to this project
 * displays the server response
   - in an iframe, since the back-end script isn't same-origin