Save if uuid conversion is complete
Add saving of UUIDs (used in the UUID Fetcher update task)
Add a new fallback method that does the exact same thing; add it when the retry on getting a UUID player would have failed twice
Check for uuids instead of usernames when loading a player
Optimize SQL side of UUID update
Add saveUserUUIDs to FlatfileDatabaseManager so mcMMO compiles

Minimal changes were made but it hasn't been tested at all and almost certainly doesn't work.
Also update flatfile with uuids
Fixed formatting!
Remove hidden interval option
Further cleanup of SQLDatabaseManager upgrades