Minor search feature fixes.

- Search textfield now properly retains focus in song selection menu.
- Clearing an invalid search no longer changes the current song.

Other changes:
- Fixed skip image not being resized correctly.
- Added menuclick sounds when selecting a new song.

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

src/itdelatrisu/opsu/states/Game.java

@@ -760,6 +760,7 @@ public class Game extends BasicGameState {
 		if (!GameImage.SKIP.isScaled()) {
 			float skipScale = (height * 0.1f) / skip.getHeight();
 			skip = skip.getScaledCopy(skipScale);
+			GameImage.SKIP.setImage(skip);
 			GameImage.SKIP.setScaled();
 		}
 		skipButton = new GUIMenuButton(skip,