merge jstween from smadar
Some serious rewriting of backward navigation

Canvas elements now contain the seeds of their own destruction.
TODO do the same with effects
Merged some CSS from the Fall
Make "master" a test page - recap moved to "six"
Appendages now save original classes in a stack

for multiple CSS changes and great justice
Re-place panels after removing chunks

also moved the origclss to the closure, if it's already there
and added test case for undoing effects, which is in TODO
Revamped undo stack and added effects to it.
Save appendee text in closure as well.

If it's already there...
Save the HTML, not the text

as the text of the chunk might contain HTML
Busy flag and default left and top properties
Merge branch 'master' into fall

Conflicts:
	index.html
	panelz.css
	panelz.js