Set an upper bound for the timer (game's timelimit)

Right now the timer has a lower bound (0) but it doesn't have an upper bound, thus when the game is starting it already starts counting beyond the game's timelimit.

For example if the timelimit is 15, and the countdown is 10 seconds, it starts counting from 15:10, which seems a bit weird. I propose this MR so the timer stays at 15:00 until the game actually starts.