The ‘syncthing-gtk’ program doesn't seem to start the syncthing daemon
automatically. In fact trying to start ‘syncthing-gtk’ through shepherd doesn't
seem to want to work at the moment, complaining that it can't close a bunch of
file descriptors.
I thought that ‘syncthing-gtk’ was a program that would fork (given the fact
that it has a ‘--quit’ command), but it turns out that it doesn't. Using the
system constructor means that shepherd will block until ‘syncthing-gtk’ is
closed.
