Updated Upstream (Spigot) (#4745)

Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Spigot Changes:
a19903d2 SPIGOT-520: Add option to disable player data saving

Spigot-Server-Patches/0232-Implement-World.getEntity-UUID-API.patch

@@ -0,0 +1,26 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Brokkonaut <hannos17@gmx.de>
+Date: Tue, 3 Jul 2018 16:08:14 +0200
+Subject: [PATCH] Implement World.getEntity(UUID) API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+index f2badcd265fe717132a377da7ca8d11d64c32871..e5e27c2ecc92f1a8c33cc7442e7034de1b4a4a84 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+@@ -1291,6 +1291,15 @@ public class CraftWorld implements World {
+         return list;
+     }
+ 
++    // Paper start - getEntity by UUID API
++    @Override
++    public Entity getEntity(UUID uuid) {
++        Validate.notNull(uuid, "UUID cannot be null");
++        net.minecraft.server.Entity entity = world.getEntity(uuid);
++        return entity == null ? null : entity.getBukkitEntity();
++    }
++    // Paper end
++
+     @Override
+     public void save() {
+         org.spigotmc.AsyncCatcher.catchOp("world save"); // Spigot