this was used for 2 things:
- to notify parent permissibles on recalculate permissions (not needed anymore thanks to callbacks)
- subscription to chat broadcast permissions (now handled separately, again using callbacks)
therefore, it's no longer needed for PermissibleBase to reference its parent, meaning that we can have one less circular dependency in our lives.
since the only way to obtain PermissionAttachmentInfo via the API is from the Permissible API, it makes zero sense to ask the attachmentinfo for its permissible, since we obviously already had it to be able to get the info in the first place. Therefore, this is just another useless reference stopping Permissibles from being garbage-collected.
lack of permission calculation means that child permissions might not have been set correctly, so this might lead to users being able to access things they aren't supposed to.
for example, Player->recalculatePermissions() was not called when a player's op status changed, nor when a permission attachment altered permissions (potential secvuln for broadcasting).
