AT&T has only just begun the transition away from 2G services with its spectrum refarming in New York City, but it now has a target end date to mark on the calendar: January 1st, 2017. Courtesy of an SEC filing, we know that the carrier hopes that both its GSM voice and EDGE data networks will have gone to the great cell tower in the sky before we're popping the champagne corks about four and a half years from now. The Big Blue Ball expects the transition to be a smooth one, as only 12 percent of its regular subscribers are usin