Fixed json parsing of resource dictionaries.
Fixed some issues with Styles/Setters. Implemented ListBoxItem, ComboBoxItem, Thumb, ScrollBar.
Implemented CheckBox, RadioButton.
Implemented ProgressBar and Slider.
Stubbed out PasswordBox, ScrollViewer.
Setter properties are not core properties.
Implemented ItemsControl, Selector, ItemCollection, ObservableCollection, SelectorSelection, ComboBox, ListBox, ScrollViewer, Popup.  Finished implementing VisualTreeHelper.