QuickUI 0.8.9 released

A minor update.

• To facilitate controls that want to perform their own layout, controls can bind to a new layout event. Catalog controls like HorizontalPanels, VerticalPanels, PanelWithOverlfow, and PersistentPanel use this to recalculate the layout of their contents in response to a change in window size.
• A companion event called sizeChanged can be triggered by a control that wants to cooperatively let its parents know about a change in the control’s size.
• A helper Control method called checkForSizeChange() can be called if a control has updated its contents and there’s the possibility that its size has changed. The helper records the control’s last known size and, if the size has indeed change, raises the aforementioned sizeChanged event.