Adds asynchronous expand/collapse functions to a table.

- A unique table ID.
- Each row needs a unique ID.
- Child rows identify their parent with a 'parentid' attribute.

In your HTML:
 $(document).ready(function() {
   $('#myTable').asyncTableTree({
     childFetchPath: "/path/to/fetch/child/data"
 });

The childFetchPath is the location of the action that will return the child rows of a given
row. This action will be sent a 'parentRowId' param.  It is expected to return one or more TR
tags as HTML. These will be injected into the existing table below the parent row.