Demos: Add test sequence to various demos
Widget: Process "classes" option during _setOption()
Autocomplete: Implement _elementsFromFromClassKey()
Accordion: Implementing _elementsFromClassKey()
Button: Implementing _elementsFromClassKey()

Also for buttonset.
Dialog: Implement _elementsFromClassKey()
Menu: Implement _elementsFromClassKey()
Progressbar: Implement _elementsFromClassKey()