Move the stack monitoring/handling to its own class
Use scrollTo jQuery plugin version 1.4.3.1

From http://flesler.blogspot.com/2007/10/jqueryscrollto.html
Refactor to allow the new StackManager to call the Debugger's callback when a stack frme has changed

The stack frame will redraw only if that frame has changed since the last
time we got a stack update - probably before the last step in/over/out/etc
Merge branch 'master' into efficient-redraws

Conflicts:
	lib/Devel/hdb/html/debugger.js
Remove the border from managed-height elements

it was just for debugging layout, and committed by accident
Refactor stack tab creation into tab element and tab content

This lets us change the label inside an existing tab if necessary
Fix sourcefile returned lines

program code always begins at index 1.

It only has a line at index 0 for the main program file where it inserts
the line 'use Devel::hdb;'
More stack frame redraw fixes

More efficiently draw stack frame info:
* The tab contents are redrawn each time, to the tooltip info (line number)
    is correct
* When finding the right tab and codePane, limit the search to the correct
    classes
* Stack frames are considered different if the subroutine name is different, too
Find the right element to scroll