when "Close to System Tray" is checked it better to add PadForge always in tray

[Jobima1st]

this is small Feature Request related to #421

when this new option ("Close to System Tray") is checked, I think it's better to always add PadForge to System Tray so we can close it (exit/quit) without the need of normally close then Exit from System Tray

[hifihedgehog]

@Jobima1st Done on v4-dev in 139f429, so it is in the next build. Settings > Window has a new option, Always Show in System Tray. With it on, the tray icon stays visible while the window is open, so Exit in its menu is always one click away. Turn it on together with Close to System Tray and you can quit from the tray without closing the window first. It is off by default.