Minor updates and code improvements.

- MusicController.getPosition() now returns time even when track is paused. (e.g. song progress bar in main menu won't reset when paused)
- Force unpause track when entering the song menu.
- Rewrote Game.RESTART_* constants as enums.
- Cleaned up logo play/exit button scaling.
- MainMenu.previous is now non-static.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/GameImage.java

@@ -257,9 +257,18 @@ public enum GameImage {
 			return img.getScaledCopy((h / 1.2f) / img.getHeight());
 		}
 	},
-	// TODO: scale MENU_PLAY and MENU_EXIT
-	MENU_PlAY ("menu-play.png", false),
-	MENU_EXIT ("menu-exit.png", false),
+	MENU_PlAY ("menu-play.png", false) {
+		@Override
+		protected Image process_sub(Image img, int w, int h) {
+			return img.getScaledCopy(MENU_LOGO.getImage().getWidth() * 0.83f / img.getWidth());
+		}
+	},
+	MENU_EXIT ("menu-exit.png", false) {
+		@Override
+		protected Image process_sub(Image img, int w, int h) {
+			return img.getScaledCopy(MENU_LOGO.getImage().getWidth() * 0.66f / img.getWidth());
+		}
+	},
 	MENU_BUTTON_MID ("button-middle.png", false) {
 		@Override
 		protected Image process_sub(Image img, int w, int h) {