Richer permissions, better BungeeCord support and various fixes!

New:

• The new achievement.count.* permission node is supported. As you may have guessed, it controls statistic increases for all achievement categories.
• A new BungeeMode configuration option was added to config.yml. If you use Advanced Achievements with a database shared across multiple servers, you've probably hit occasional data synchronisation problems, which this option aims to fix.

Improvement:

• Users who leave BungeeMode set to false should see a slight performance boost compared to older versions of the plugin.

Fixes:

• Fixed a memory leak that was introduced in version 5.16.0. Player statistics were being kept in the server's RAM even several hours after players had disconnected.

• The achievement.* permission now covers individual achievement permissions (e.g. achievement.place_100_stone).

• The achievement.* permission now covers the achievement.add permission for the /aach add command.

Other:

• The PooledRequestsTaskInterval configuration parameter was dropped. Its purpose was obscure and could lead to problems if misused.