Final build. Fixes #1327

The battle for GC being on and off is finally over, GC stays off.
Agarian Skies servers recommended to turn on. IC2, EnderIO, BOP servers
are recommended it remains off.

To alter setting, use bukkit.yml and change chunk-gc.enabled to false or
true.

This is the final 1.6.4 build.
Added configurable TileEntity tick settings. Refactored configuration.

With this new change, each TileEntity that attempts to tick will be added
to cauldron.yml under world-settings. There are currently 2 options for
each TileEntity.

The first option is 'tick-no-players'
- This prevents ticks on a TileEntity if there are no players in range
  excluding forced chunks with chunkloaders.
  The default value is false. Setting this to true will make it tick with
  no players nearby. This setting should be set to true for TileEntities
  that need to always tick such as ComputerCraft's computer.

The second option is 'tick-interval'
- This controls how often you want this specific TileEntity to tick. The
  default is 1 which means you want it to tick every tick. Changing this
  to a value of 20 would mean it would tick every 20 ticks.

The default config will apply to all worlds. If you want to override a
specific TE in a world, you would add it to cauldron.yml like the example
below :

world-settings:
  worldname:
    tileentities:
      net-minecraft-tileentity-TileEntityChest:
        tick-no-players: false
	tick-interval: 1

* Fixed many configuration bugs. You can now modify anything in
cauldron.yml then execute '/cauldron reload' to have it take effect in
game. For other configuration options use the '/cauldron' command.
* Added StructureStart NPE check to prevent crashes with broken structure
components.
* ChunkGC is disabled again by default. If you experience a high chunk load, enable
chunk-gc in bukkit.yml. Note: as stated in previous commits, you may
experience issues with mods with ChunkGC turned on.