Updated version number to 1.5.2.1

Updated version number to 1.5.2.1.
Build against Bukkit-1.6.4-R2.0

Build against Bukkit-1.6.4-R2.0.
Updater now checks if update files are approved

The Auto Updater will now check whether the udpate file has been
approved yet by the Bukkit administartors, the update will only be
downloaded and installed if it has been approved. (Bukkit Rule)