Outdoor companies are latest to act after shooting in Florida
                                
                                
                                    (Newser) -
                                    Dick's ,  Walmart , and  Kroger  have all tightened their rules regarding gun sales since the Feb. 14 massacre at Marjory Stoneman Douglas High School in Parkland, Fla., and now a fourth major retailer has joined their ranks. A "superfan" on Twitter Thursday night  implored  the outdoor-recreation retailer to...