v3.1

• added: group visibility and membership
• added: option to export groups owned for users
• added: plugin setting to cleaup older finished exports
• added: time constraints to the export settings
• changed: csv processing is now offloaded to the minute cron
• changed: get export value moved to class callbacks
• changed: moved exportable values hook to class callback
• fixed: disallow commenting on exports
• fixed: generic handling of array export values
• fixed: possible error if seperator > 1 char
• fixed: possible invalid return for group last activity
• fixed: undefined class in upgrade script
• fixed: wrong display of array values in preview