Use distance map to optimise entity tracker / Misc Utils

Use the distance map to find candidate players for tracking.

This also ports a few utility changes from Tuinity

Spigot-API-Patches/0203-Add-Mob-Goal-API.patch

@@ -1,4 +1,4 @@
-From 3837658c3b4d01d6c8ef94bc972a644eb77e222f Mon Sep 17 00:00:00 2001
+From b9fa8d98289a044c4bc231ef79435e27d829a5de Mon Sep 17 00:00:00 2001
 From: MiniDigger <admin@minidigger.me>
 Date: Fri, 3 Jan 2020 16:24:46 +0100
 Subject: [PATCH] Add Mob Goal API
@@ -462,5 +462,5 @@ index 957a6016..4fecbe94 100644
      /**
       * Check if this is tamed
 -- 
-2.17.1
+2.26.0