New demo for easing effects

Hi,
I just added a demo to trunk that visualizes the easing effects:
http://jquery-ui.googlecode.com/svn/trunk/demos/index.html#effect|easing
The drawing still needs some tuning, the steeper curves aren't
rendered properly. I also couldn't figure out why "linear" and
"jswing" can't be rendered that way...
Jörn