TreeView: Display a collapsible tree of links

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Audiences Experience Level

Patrons reading this file should be comfortable using a text editor, 
managing files and be familiar with PHP.  Some changes to file paths 
are required.  

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Development Environment

This code was originally developed using a Windows platform and may not
work without modification on a Unix or Mac environment.  

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Code Changes

In order to use these files you are must adjust their include_once directives.
Failure to do still will cause the example scripts to fail.

You must also update the dirPath() function where ever found to provide the 
right depth for the files to locate the Web Root.

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Required Classes

This class is specifically designed to use Ladder.  Ladder manages the data
that this class presents.  This class will NOT work with standard SQL
appliations.

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Recommended Directory Structure

Web Root
 | - [Application]
 | -  | - TreeView.php
 | -  | - trgr_TreeView.js
 | -  
 | - Install
 | -  | - install.php [ from Ladder ]
 | -  
 | - Images
 | -  | - Ladder
 | -  | -  | - empty.gif
 | -  | -  | - file.gif
 | -  | -  | - folder_closed.gif
 | -  | -  | - folder_open.gif
 | -  | -  | - reference.gif
 | -  | -  | - plus.gif
 | -  | -  | - minus.gif
 | -  
 | - Shared
 | -  | - _app.inc
 | -  | - styles.css
 | -  | - functions.inc
 | -  | - install_functions.inc
 | -  | - GPL.txt
 | -  | - 
 | -  | - Classes
 | -  | -  | - Ladder
 | -  | -  | -  | - Ladder_Globals.cls
 | -  | -  | -  | - Ladder_Folder.cls
 | -  | -  | -  | - Ladder_Item.cls
 | -  | -  | -  | - Ladder_Properties.cls
 | -  | -  | -  | - Ladder_References.cls
 | -  | - 
 | -  | - Panels
 | -  | -  | - Panel_Panel.cls
 | -  | -  | - Ladder 
 | -  | -  | -  | - Panel_Folder_DetailList.cls
 | -  | -  | -  | - Panel_TreeView.cls