[SPIGOT-946] Begin making use of access transforms to simplify patching.

By: md_5 <git@md-5.net>

paper-server/nms-patches/InventorySubcontainer.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/server/InventorySubcontainer.java
 +++ b/net/minecraft/server/InventorySubcontainer.java
-@@ -3,15 +3,56 @@
+@@ -3,6 +3,12 @@
  import com.google.common.collect.Lists;
  import java.util.List;
  
@@ -13,9 +13,7 @@
  public class InventorySubcontainer implements IInventory {
  
      private String a;
-     private int b;
--    private ItemStack[] items;
-+    public ItemStack[] items; // CraftBukkit - public
+@@ -11,7 +17,42 @@
      private List<IInventoryListener> d;
      private boolean e;