initial commit
Countdown.java - decoupled it from GUI
ClockUpdater.java - created class to take care how, remaining time is
presented
IntervalTimerApp.java - implemented Countdown display (hours, minutes,
seconds, colon-separated)
ClockUpdater.java - implemented updateLabels(int) and resetLabels()
ClockUpdater.java - implemented Listener-method: decreases
remainingSeconds counter and updates the displayed countdown digits
IntervalTimerApp.java - bugfix
hour and second-label were in the wrong order changed display from
ss:mm:HH to HH:mm:ss
ClockUpdater.java - bugfix
in startCountdown method, the Countdown needs to be started via its
start() method
Merge remote-tracking branch 'choose_remote_name/master'