new variation of demos: ability to dynamically append new data

* the script (jQuery plugin) does NOT currently support the usage pattern:
  - initialize table with plugin
  - update table, adding new rows
  - reinitialize table with plugin

* this commit adds another variation of the demos,
  which illustrates how the script CURRENTLY behaves
  when data is dynamically added to a table
  that has already been initialized by the plugin

* the next commit will update the script,
  giving it the ability to detect this usage pattern,
  and reinitialize the table accordingly.

* the demos introduced in this commit will work after the next commit.
  the demos are being pushed first, to allow a functional comparison.
can now add new rows to table after initialization

usage pattern:
 * table is built (either server-side, or client-side)
 * table is initialized:
     $table.table_multi_row_selectable_drag_drop(options)
 * table is modified..
   new rows are added via client-side script
 * table is reinitialized:
     $table.table_multi_row_selectable_drag_drop()
   which is necessary to bind event handlers to elements:
     - `select_handle`
     - `drag_handle`
 * this is necessary,
   since jQuery `delegates` are not (currently) used.
   I have no immediate intention to rewrite the script
   to bind event handlers using `delegates`.