2016-07-24: added missing tunnel handling
2016-07-28: fix for missing item
2018-05-02: code cleanup, rewrite of check and inventory function
2020-06-08: changed snmp-scan function
2021-09-01: rewritten for CMK 2.0
2022-10-23: fixed warning in upgrade "non-empty params vanished" for vpn_entry
2023-05-29: moved gui files to ~/local/lib/check_mk/gui/plugins/...
2023-10-28: moved from ~/local/lib/check_mk/gui/plugins/wato to ~local/lib/check_mk/gui/plugins/wato/check_parameters
            fixed crash on empty l2lpeerobjname (THX to andreas doehler)
            renamed parameters. needs tabularasa
            removed ":" from service name
            some cleanup