By Robert Mackey September 8, 2010 6:02 pm September 8, 2010 6:02 pm A message posted on Twitter last week by a reporter who was being held by Afghan militants. A Japanese journalist who was released this week after being held captive in Afghanistan for five months explained on Tuesday how he had managed to post two updates on Twitter from the phone of one of his captors. Kosuke Tsuneoka, who was