Added getHighestBlockYAt

By: FrozenCow <frozencow@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -43,6 +43,10 @@ public class CraftWorld implements World {
         return block;
     }
     
+    public int getHighestBlockYAt(int x, int z) {
+    	return world.d(x, z);
+    }
+
     public Chunk getChunkAt(int x, int z) {
         ChunkCoordinate loc = new ChunkCoordinate(x, z);
         Chunk chunk = chunkCache.get(loc);