3.16.0

• add email replacement vars filter, so you can add previews for your own emails
• change b3_get_user_approval_link() to b3_get_user_approval_url()
• change meta keys to reflect their function better
  • b3_activate_debug_info
  • b3_activate_domain_restriction
  • b3_activate_front_end_approval
  • b3_activate_honeypot
  • b3_activate_privacy_page
  • b3_activate_username_restriction
• add new filters
  • b3_activate_debug_info
  • b3_preview_email_message
  • b3_preview_email_subject
  • b3_replacement_vars
• removed b3_redirect_after_register filter