gameboy: stretch gui window; rm unused tile-window

src/gameboy.rs

@@ -71,18 +71,8 @@ impl GameBoy {
             minifb::WindowOptions {
                 resize: false,
                 title: true,
-                scale_mode: minifb::ScaleMode::UpperLeft,
-                ..minifb::WindowOptions::default()
-            },
-        ).expect("Unable to create window");
-        let tiles = minifb::Window::new(
-            "tiles",
-            LCD::TILE_WIDTH,
-            LCD::TILE_HEIGHT,
-            minifb::WindowOptions {
-                resize: false,
-                title: true,
-                scale_mode: minifb::ScaleMode::UpperLeft,
+                scale: minifb::Scale::X2,
+                scale_mode: minifb::ScaleMode::Stretch,
                 ..minifb::WindowOptions::default()
             },
         ).expect("Unable to create window");