Test mode of `nut.exe` wrapper on Windows leaves daemons running after Ctrl+C

[jimklimov]

The nut.exe program started as a service wrapper; however it grew to be a useful troubleshooting tool for development and setup alike, with the -N (non-service) option.

Unfortunately once it starts NUT daemons correctly, there is no way to easily kill them with the wrapper (can be done in Task Manager etc.)

For experiments to cycle easily, want support for Ctrl+C to kill the daemons when exiting (maybe staggered - e.g. "press twice within a second" for this mode, so there IS a way to keep daemons running).