Added Spawner functionality.

Added /cor region commands and permissions.
Spawners and commands have been tested thoroughly, but bugs might still occur.
 Unfortunately, it seems Minecraft/Bukkit loads chunks as soon as a spawner is enabled on one of them,
 even though intended functionality is to only activate spawners when their center chunk is loaded due to Player presence.
 If this is indeed the case, and if so, can be fixed remains to be seen.