#1206 clock update delayed up to 1 minute after resume

[Dmytro Bagrii]

When clock toolbar is configured to display time without seconds (e.g. session.screen0.strftimeFormat is "%H:%M"), after resuming from suspend/hibernation the clock displays wrong time for up to 1 minute (in worst case).
Quick dirty fix would be to remove timeout multiplication by 60 in ClockTool.cc calcNextTimeout(). However, this will lead to excessive wakeups every second, which is not desirable.
Other option for workaround is to implement some IPC method to force call ClockTool::updateTime() externally (or even to force redraw entire GUI). This call can be triggered e.g. by systemd unit configured to run after resuming from suspend/hibernation in systemd-based distros.