Increase animation speed of accordion pane

The animation of the Accordion (and possibly other controls?) is slow and does not follow common UX guidelines.

I would estimate it to be around 7-800ms. A more normal would be around 300ms.

For reference on a very good speed see the animations in OS X (e.g. expanding a folder in the tree control). They convey the action (which is the purpose) but doesn't make the user halt and wait more than absolutely necessary.

An animation should generally as fast as possible without being undetectable if you happen to blink at that exact moment.