Piers Morgan finally exits CNN; vows to NRA: 'I haven't finished with you'

Piers Morgan took to Twitter to announce his decision to cut ties with CNN, during which he also sent a stark message to the National Rifle Association: I'm still gunning for you. "BREAKING NEWS: I am no longer a @CNN employee," Mr. Morgan first tweeted Tuesday. He then tweeted: "I was offered a new 2-year deal…