Report: 49ers, Browns aggressively pursuing Jackson

The mystery of the DeSean Jackson mystery teams apparently has been solved, without the intervention of Shaggy, Scooby-Doo, or any other meddling kids. According to NBC Washington, the 49ers and Browns are pursuing Jackson, who continues to visit with the Redskins.  Per Diana Russini of NBC Washington, the 49ers reached out to Jackson while he…