Make generic break be a short break
Add definition of long break time and complete count
Add long break segment to pomodoro struct
Implement a long break every four completed pomodoros
Merge branch 'long-break': implement long breaks every 4 pomodoros

* long-break:
  Implement a long break every four completed pomodoros
  Add long break segment to pomodoro struct
  Add definition of long break time and complete count
  Make generic break be a short break
Update README to make it more useful