Stop saving users on the main thread
Save async in commands and ExperienceAPI, too
Remove mistakenly committed file
Merge remote-tracking branch 'remotes/upstream/master'
Save users asynchronously
Remove PvpLogger checks

No longer needed when testing with Combat Tag v6.1.4, the NPCs have
metadata „NPC”.

Fixes #2017
Fix an IndexOutOfBoundsException: Index: 0

In SaveTimerTask.java

Fixes #2039
Update changelog
Merge branch 'master' of https://github.com/mcMMO-Dev/mcMMO