CHANGELOGS :
- Added bossbar configurable delay + bossbar configurable color
- Added configurable rewards for when a player finishes all quest in a service
- Possibility to use the player's head in the GUI
- Fixed a bug with "on_click" section in GUI item not being properly registered
- Added a Glitch Checker to the plugin to avoid player abusing quest.
- Fixed COOK, CRAFT and VILLAGER_TRADE type not give the right amount of point.
- Fixed a NPE with the placeholders if the player's data were not loaded
- Fixed an issue with quest not being incremented correctly
- Fixed an issue with the glitch checker
- Fixed concurrency issue in the GUI making some items invisible.
- Fixed an issue with entity types not being registered properly
- Fixed an issue with GATHER_ITEM type not being actualized properly.
- Fixed an issue with type LAUNCH not working properly
- Fixed an issue with type CARVE not being registered properly
- Added some configurable messages + "bukkit-messages.yml"

Thanks to RavenskyPaul for his help with this update, finding all those bugs !