Free agency s trudging on and the San Francisco 49ers have been busy making roster changes. Let's take a look at what has gone on so far:Returning free agents: receiver Anquan Boldin, kicker Phil Dawson, cornerback Eric Wright.2015 free agents extended: Center Daniel Kilgore, fullback Bruce Miller.Departed free agents: Safety Donte Whitner (Cleveland), cornerback Tarell Brown (Oakland), running back Anthony Dixon (Buffalo), receiver Mario Manningham (Giants).