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/Optimize-ItemStack.isEmpty.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Optimize ItemStack.isEmpty()
 Remove hashMap lookup every check, simplify code to remove ternary
 
 diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
-index a8f7ff98..9465f4c1 100644
+index a8f7ff98f..9465f4c16 100644
 --- a/src/main/java/net/minecraft/server/ItemStack.java
 +++ b/src/main/java/net/minecraft/server/ItemStack.java
 @@ -0,0 +0,0 @@ public final class ItemStack {