Added a bunch of functions for better item optimization.

Items can be stored to a ID with /lootchest saveitem <id> and can be retrieved with /lootchest getitem <id>.

Also added a /lootchest reload command that is used to reload the configuration files if you made any changes directly to the files while the server is running.

Added /lootchests cooldown command and added cooldown time remaining to cooldown message.

Fixed an NPE that happened after reloading the plugin.