Lightning, Grace message, EXP/Level reset

* Fix for http://dev.bukkit.org/server-mods/myhungergames/tickets/44-show-message-at-the-beginning-and-end-of-grace-period/
* Fix for http://dev.bukkit.org/server-mods/myhungergames/tickets/45-lightning-on-death-and-when-only-x-players-are-left/
* InventorySave will now save/reset level and exp