2016-04-08: initial release
2016-08-22: removed index column
2018-08-04: changed scan function, code cleanup
2018-09-04: changes for CMK 1.5.x (inv_tree --> inv_tree_list)
2020-03-15: added support for CMK1.6x
2021-07-11: rewritten for CMK 2.0
2021-07-15: added support for Catalyst 9800 Controllers
2023-06-07: moved gui files to ~/local/lib/chek_mk/gui/plugins/...