Before I get to the changes, i quickly want to mention that in the next big version there will be a complete recode of the AdvancementManager since there was just stuff added every update without taking old things into account etc... It has become very difficult to fix some problems because of the current way it has been programmed. I will try to keep as many methods the way they are now, but the behind-the-scene stuff will definitely change a lot!

New Features:
- Added grantAdvancement(UUID uuid, Advancement advancement), revokeAdvancement(UUID uuid, Advancement advancement), grantCriteria(UUID uuid, Advancement advancement, String... criteria), revokeCriteria(UUID uuid, Advancement advancement String... criteria), setCriteriaProgress(UUID uuid, Advancement advancement, int progress), getCriteriaProgress(UUID uuid, Advancement advancement), getProgressJSON(UUID uuid), getProgressJSON(UUID uuid, String namespace), saveProgress(UUID uuid, String namespace) to AdvancementManager to also support these features for offline offline players
This lead to the additions of the following events:
OfflineAdvancementGrantEvent, OfflineAdvancementRevokeEvent, OfflineCriteriaProgressChangeEvent