President-elect Donald Trump has tapped retired Lt. Gen. Michael Flynn to become his national security adviser, a source with knowledge of the matter has revealed. The source told NBC Wednesday evening that Trump had settled on Flynn, who was also being considered for the secretary of defense post. The Daily News could not independently confirm the report, and the Trump campaign did not immediately return a request for comment. Earlier in the evening, Trump spokesman Jason Miller said the President-elect had met with Flynn and added he would make a "fantastic addition" to the team. "He has been a companion...