Minor changes.

- Replaced duplicate GameImage.process_sub() calls from related images with calling a single method, for easier editing.
- Suppress warnings from overwritten Slick2D classes.

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

src/itdelatrisu/opsu/states/Game.java

@@ -701,7 +701,7 @@ public class Game extends BasicGameState {
 			resetGameData();
 
 			// needs to play before setting position to resume without lag later
-			MusicController.play();
+			MusicController.play(false);
 			MusicController.setPosition(0);
 			MusicController.pause();