B65-ZK-1534: Spinner no longer supports null value
F65-ZK-1507: Client-side API to register a callback function that can be invoked after all widgets finish resize
B65-ZK-1557: Groupbox fails to open if it has non-visible children
B65-ZK-1593: JS bug - Failed to mount: Cannot read property 'defaultView' of null
B65-ZK-1567: Menuitems not aligned below Menu
B60-ZK-1613: Invoke response.sendError in Weblogic server, the server will render the message as a response body
Merge branch '6.0'
B65-ZK-1614: Full Screen iPad Web Apps Missing Component Buttons
B65-ZK-1609: Tree close/open icon is not correct after calling clearOpen and reopen a node
B65-ZK-1608: Tree node become leaf node after update
Fix bug: B65-ZK-1568
- Window is always visible when switching to non-modal mode
  e.g. <window visible="false" mode="overlapped" /> would be visible
       <window mode="overlapped" visible="false" /> would be invisible
Fix bug ZK-1526: layouts and containers should not take menupopup into account when computing padding
http://tracker.zkoss.org/browse/ZK-1526