Added "Easy" mod.

- Halves all difficulty values and grants 3 "lives" instead of 1, with a score multiplier of 0.5x.

Other changes:
- Fixed score display in game state if score exceeds 8 digits.
- Added a "HP_DRAIN_MULTIPLIER" constant for steady HP drain/increase (to replace numeric constants).

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

src/itdelatrisu/opsu/objects/Slider.java

@@ -575,7 +575,7 @@ public class Slider {
 		if ((game.isInputKeyPressed() && distance < followCircleRadius) || isAutoMod) {
 			// mouse pressed and within follow circle
 			followCircleActive = true;
-			score.changeHealth(delta / 200f);
+			score.changeHealth(delta * GameScore.HP_DRAIN_MULTIPLIER);
 
 			// held during new repeat
 			if (isNewRepeat) {