fix: redraw too late after system wakeup.

[tangxinfa]

The time text displayed always wrong after system wakeuped, fix it by schedule the redraw timer at every second, and redraw screen only if time text require to change.

[tangxinfa]

I try to launch i3lock before system hibernate, after wake up the time displayed is not updated in time.

The root cause maybe because the LID is closed or the screen is shutdown, so we can't guarantee the time displayed will always take effects.

We can simply use a one second repeat timer to fix this problem.