Revert previous change to clear chunk list on the end of each tick, make it configurable instead.

Whilst the new behaviour was technically correct as it prevented the possibility of the chunk tick list actually increasing over time, it introduced a few issues, namely the fact that it slowed growth to unreasonable levels, and interfered with the values which server admins have finally tuned, and come to enjoy over the last few years.
If it is absolutely essential that growth be halted and ticking reduced as much as possible, the config option is there for power users.
If we wish to 'fix' this by default in the future, a new chunk ticking algorithm, which actually has meaningful config options should be designed.

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

CraftBukkit-Patches/0023-Entity-Tracking-Ranges.patch

@@ -1,4 +1,4 @@
-From 723a29a9f8ab6121ab7a9059b67155bc10104131 Mon Sep 17 00:00:00 2001
+From 9b5ea03810a7d9eb28ced82c271b59988a7ac21b Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Wed, 20 Feb 2013 11:58:47 -0500
 Subject: [PATCH] Entity Tracking Ranges
@@ -24,10 +24,10 @@ index 97d0bbb..fc679ae 100644
              i = this.e;
          }
 diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
-index f7c6166..92497f5 100644
+index 1d95207..43f7fd8 100644
 --- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
 +++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
-@@ -145,4 +145,19 @@ public class SpigotWorldConfig
+@@ -149,4 +149,19 @@ public class SpigotWorldConfig
          miscActivationRange = getInt( "entity-activation-range.misc", miscActivationRange );
          log( "Entity Activation Range: An " + animalActivationRange + " / Mo " + monsterActivationRange + " / Mi " + miscActivationRange );
      }