Show next-actions round-robin

[fniessink]

  Given a todo.txt with
      """
      Task A
      Task B
      """
  When the user asks for the next action
  Then Next-action show "Task A"
  When the user asks for the next action
  Then Next-action show "Task B"
  When the user asks for the next action
  Then Next-action show "Task A"