TAB toggles UI visibility in the demo

demo/common/src/lib.rs

@@ -341,6 +341,13 @@ impl<W> DemoApp<W> where W: Window {
                         self.dirty = true;
                     }
                 }
+                Event::KeyDown(Keycode::Tab) => {
+                    self.options.ui = match self.options.ui {
+                        UIVisibility::None => UIVisibility::Stats,
+                        UIVisibility::Stats => UIVisibility::All,
+                        UIVisibility::All => UIVisibility::None,
+                    }
+                }
                 Event::OpenSVG(ref svg_path) => {
                     let built_svg = load_scene(self.window.resource_loader(), svg_path);
                     self.ui.message = get_svg_building_message(&built_svg);

demo/common/src/window.rs

@@ -57,6 +57,7 @@ pub enum Event {
 pub enum Keycode {
     Alphanumeric(u8),
     Escape,
+    Tab,
 }
 
 #[derive(Clone, Copy, Debug)]

demo/native/src/main.rs

@@ -227,6 +227,7 @@ impl WindowImpl {
     fn convert_sdl_keycode(&self, sdl_keycode: SDLKeycode) -> Option<Keycode> {
         match sdl_keycode {
             SDLKeycode::Escape => Some(Keycode::Escape),
+            SDLKeycode::Tab => Some(Keycode::Tab),
             sdl_keycode if sdl_keycode as i32 >= SDLKeycode::A as i32 &&
                     sdl_keycode as i32 <= SDLKeycode::Z as i32 => {
                 let offset = (sdl_keycode as i32 - SDLKeycode::A as i32) as u8;