More graphical updates, some code cleanup, and minor fixes.

- The MenuButton class now fully supports hover effects (scale, fade, rotate) for Animations.
- Used a fixed location for the selection buttons in the song menu (previously based on the "back" button width, which varies widely in different skins).
- Added hover effects for "retry" and "exit" buttons in the ranking screen.
- Changed animation speed of back/skip buttons.
- Fixed a bug where main menu showed the incorrect number of songs loaded during searches.
- Removed unneeded draw() methods in Utils for color filters (since 69f5aa5).
- Moved Utils.drawCentered(Image, ...) into the Image class.
- Added overwritten Image class to Maven excludes.

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

src/itdelatrisu/opsu/objects/curves/LinearBezier.java

@@ -164,9 +164,9 @@ public class LinearBezier extends Curve {
 		Image hitCircle = GameImage.HITCIRCLE.getImage();
 		Image hitCircleOverlay = GameImage.HITCIRCLE_OVERLAY.getImage();
 		for (int i = curve.length - 2; i >= 0; i--)
-			Utils.drawCentered(hitCircleOverlay, curve[i].x, curve[i].y, Utils.COLOR_WHITE_FADE);
+			hitCircleOverlay.drawCentered(curve[i].x, curve[i].y, Utils.COLOR_WHITE_FADE);
 		for (int i = curve.length - 2; i >= 0; i--)
-			Utils.drawCentered(hitCircle, curve[i].x, curve[i].y, color);
+			hitCircle.drawCentered(curve[i].x, curve[i].y, color);
 	}
 
 	@Override