Enable arrow key navigation of Table of Contents

[GoogleCodeExporter]

Enhancement Request

Enable up and down arrow keys for navigating pages using Table of Contents next 
and previous 
page feature. However, define "next" as being the next item at the *same* level 
of the hierarchy 
rather than expanding the hierarchy to the next item in the list.

Use the right arrow key to drill deeper into the hierarchy.
Use the left arrow key to back up to the parent level.

Original issue reported on code.google.com by msinclai...@gmail.com on 19 Nov 2008 at 2:29