Make spawner nerfed mobs float AI toggleable

closes GH-57

Spigot-Server-Patches/Player-Exhaustion-Multipliers.patch

@@ -9,8 +9,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
-         fishingMaxTicks = getInt("fishing-time-range.MaximumTicks", 900);
-         log("Fishing time ranges are between " + fishingMinTicks +" and " + fishingMaxTicks + " ticks");
+     private void nerfedMobsShouldJump() {
+         nerfedMobsShouldJump = getBoolean("spawner-nerfed-mobs-should-jump", false);
      }
 +
 +    public float blockBreakExhaustion;