Added an optional feature which saves the backpacks on the InventoryClick event to a hashmap. Since Bukkit doesn't handle the PlayerQuit event correctly, the hashmap is saved to file on PlayerLogin. This can be enabled in the config.yml and it fixes the item dupe glitch.

Signed-off-by: seifpic <seifpic@hotmail.com>
Merge pull request #2 from seifpic/master

Dupe glitch fix