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/0008-Merge-tweaks-and-configuration.patch

@@ -1,4 +1,4 @@
-From 6117d1cfc54f4e894a7607003baa1c54cb3ba9bd Mon Sep 17 00:00:00 2001
+From 3499d77354a84df9ce6e49d5dba39a0a471b3ff8 Mon Sep 17 00:00:00 2001
 From: md_5 <md_5@live.com.au>
 Date: Sat, 23 Mar 2013 09:46:33 +1100
 Subject: [PATCH] Merge tweaks and configuration
@@ -69,10 +69,10 @@ index 53ab411..d90d5a4 100644
          if (event != null && (event.isCancelled() || entity.dead)) {
              entity.dead = true;
 diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
-index f38bb25..9f07e71 100644
+index ddca7c3..185442a 100644
 --- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
 +++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
-@@ -106,4 +106,18 @@ public class SpigotWorldConfig
+@@ -110,4 +110,18 @@ public class SpigotWorldConfig
          saplingModifier = getAndValidateGrowth( "Sapling" );
          wheatModifier = getAndValidateGrowth( "Wheat" );
      }