Added bstats tracking to this as well

stats for this can be seen here:
https://bstats.org/plugin/bungeecord/XBungeeFriends/10796

Updates coming later:
- friend notify:
- join: notifies you when a friend is online
- leave: notifies you when a friend leaves
- change server: notifies you when a friend changes server
- changes to friends list:
- will now show what server they're playing on when you hover over their name