Updated Upstream (Paper)

Upstream has released updates that appears to apply and compile correctly

Paper Changes:
21faf822 Implement optional per player mobspawning (#2171)
88722ec8 Prevent consuming the wrong itemstack (#2477)
294e3046 Async chunk api/io/loading (#2308)

patches/server/0055-Advancement-stuffs.patch

@@ -0,0 +1,24 @@
+From 19494803caeaf400fd2e4f5a61c3077ec08a4eab Mon Sep 17 00:00:00 2001
+From: William Blake Galbreath <blake.galbreath@gmail.com>
+Date: Sun, 11 Aug 2019 22:25:33 -0500
+Subject: [PATCH] Advancement stuffs
+
+---
+ src/main/java/net/minecraft/server/CriterionTrigger.java | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/src/main/java/net/minecraft/server/CriterionTrigger.java b/src/main/java/net/minecraft/server/CriterionTrigger.java
+index 4fe732447..6e5d81daf 100644
+--- a/src/main/java/net/minecraft/server/CriterionTrigger.java
++++ b/src/main/java/net/minecraft/server/CriterionTrigger.java
+@@ -27,6 +27,7 @@ public interface CriterionTrigger<T extends CriterionInstance> {
+             this.c = s;
+         }
+ 
++        public T getInstance() { return a(); } // Purpur - OBFHELPER
+         public T a() {
+             return this.a;
+         }
+-- 
+2.23.0.rc1
+