add release date
decouple Flashchart component from zul.jar to flashchart.jar and move its source to Github - https://github.com/zkoss/flashchart
release 5.0.12
update version to 5.0.13
Fix bug ZK-1523
http://tracker.zkoss.org/browse/ZK-1523
Fix bug ZK-1572: Scrolling-Bug in Listbox with freezed columns with ie9
http://tracker.zkoss.org/browse/ZK-1572