FileDialogVidget introduced
Xwt.WpfBackend.CanvasBackend: try to optimize
Xwt.Gtk CairoContextBackendHandler: draw text on baseline
Xwt.Wpf.WidgetBackend: catch mousevents out of widgets bounds (similar to GTK)
Xwt.Gtk: revert clipping in CanvasBackend (not needed)
whitespace
Xwt: more public
IVidget: publish Backend in interface
MoveResizeRenderer: remove Backend.Update()