Further additions to the MonkeyTester application:

- platform preferences monitor
- improved pages: hbox, vbox
- improved css playground
- mouse listener option in some context menus
- additional choices: background
- additional properties: Node::clip, Region::shape, TextInputControl::textFormatter
- font selector in Tools -> JTextArea/JTextField Embedded in SwingNode

## New Pages
- anchor pane
- border pane
- button bar
- flow pane
- grid pane
- media player
- progress indicator
- separator
- slider
- stack pane
- stage
- tile pane