Add extra mutation methods to Color
Add the Wrapper interface
Modify gui_textfield_texture.png and add gui_textfield_border.png
Add methods to FontFormat to get current settings
Modify Operation to extend Runnable
Add Metadata#clearData and Metadata#toString
Add a static File field to Resources to represent the resource root dir
Add default Screen#offer, add Screen#getGame
Store a Screen reference in ScreenElement
Modify ScreenElement and TickableOverlay to store a Wrapper<Boolean>
Remove old util.game.Visibility
Add new impl.ui.Visibility as an implementor of Wrapper<Boolean>
Modify TestGame implementation to bring in line with recent changes