anchor.diff:  import 'dart:async';
   
   import 'package:angular2/angular2.dart';
  +
  +enum ClockState{
  +  pomodoro,
  +  rest
  +}
   
   @Component(selector: 'clock')
   
  
positive.code: <button (click)="start()">Start</button>
  <button (click)="stop()">Stop</button>
  <button (click)="reset()">Reset</button>
  <p>Pomodoro duration: <i>{{ durationPomodoro }}</i>
  <input #durationpomodoro>
  <button (click)="setDurationPomodoro(durationpomodoro.value)">change</button>
  
negative.code:     String second = (s <= 9) ? '0$s' : '$s';
      return '$minute:$second';
    }
  
    bool isPomotime(){
      return currentState == ClockState.pomodoro;
    }
  }