xmlui: scroll/size fixes: - VerticalContainer and TabsPanelContainer are now put in ScrollView - the height hack in TabsContainer has been removed has it is not needed anymore (minimum_height is now available) - remove the empty widget which was added at the end of main panel, it's better to have the UI taking the whole container height - fixed height for TextWidget,LabelWidget and JidWidget - better scrollbar for VerticalContainer and TabsPanelContainer