If a full refresh is done from within the app (`cmd + r`) restart the
onboarding process from the beginning, including stopping lnd and
disconnecting any active connections.
Fix#641
On darwin, we keep the app running and just hide it when the window is
closed as that is the standard convention. On linux and windows the app
should be quit when the window is closed.
This resolves an issue where on linux/windows the app would remain open
when the window is closed, with no way to properly quit it short of
doing a force quit.
Tom Kirkpatrick