/s/f/v in valueFromSlice
Button: Add CheckedChanged event
declarative/Builder: Defer Container.SetDataBinder call until after initProperties

This is to make it work for Composite and other non top level widgets, as previously only DataBinders on MainWindow and Dialog were initialized properly.
declarative/Builder: Don't complain about conflicting Property/value types if the property returns nil
DataBinder: Add support for automatic submit on widget property change
RadioButton: Add data binding support