Get desktop application:
View/edit binary Protocol Buffers messages
https://wiki.hoggitworld.com/view/DCS_Class_Group
https://wiki.hoggitworld.com/view/DCS_func_activate
(message has no fields)
https://wiki.hoggitworld.com/view/DCS_func_destroy
(message has no fields)
https://wiki.hoggitworld.com/view/DCS_func_getUnits
Whether the response should include only active units (`true`), only inactive units (`false`), or all units (`nil`).