Optimize Hoppers

- Lots of itemstack cloning removed. Only clone if the item is actually moved
- Return true when a plugin cancels inventory move item event instead of false, as false causes pulls to cycle through all items.
  However, pushes do not exhibit the same behavior, so this is not something plugins could of been relying on.
- Add option (Default on) to cooldown hoppers when they fail to move an item due to full inventory
- Skip subsequent InventoryMoveItemEvents if a plugin does not use the item after first event fire for an iteration

Spigot-Server-Patches/LivingEntity-setKiller.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] LivingEntity#setKiller
 
 
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
-index b9e106031..413bab0c9 100644
+index d4d51688c..a7b076377 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
 @@ -0,0 +0,0 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {