Mark chunk dirty on entity changes

This is to hopefully help avoid any chunk saving entity issues.
Marks the chunk that it NEEDS to be saved, ensuring the latest state gets saved.

Spigot-Server-Patches/Mark-chunk-dirty-anytime-entities-change-to-guarante.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Mon, 23 Jul 2018 22:18:31 -0400
+Subject: [PATCH] Mark chunk dirty anytime entities change to guarantee it
+ saves
+
+
+diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
+index b31c301ec..6de053781 100644
+--- a/src/main/java/net/minecraft/server/Chunk.java
++++ b/src/main/java/net/minecraft/server/Chunk.java
+@@ -0,0 +0,0 @@ public class Chunk {
+         entity.ad = this.locZ;
+         this.entitySlices[k].add(entity);
+         // Paper start
++        this.markDirty();
+         entity.setCurrentChunk(this);
+         entityCounts.increment(entity.entityKeyString);
+         if (entity instanceof EntityItem) {
+@@ -0,0 +0,0 @@ public class Chunk {
+ 
+         // Paper start
+         if (!this.entitySlices[i].remove(entity)) { return; }
++        this.markDirty();
+         entity.setCurrentChunk(null);
+         entityCounts.decrement(entity.entityKeyString);
+         if (entity instanceof EntityItem) {
+--