Spectrum Brands Holdings Inc., the Middleton manufacturer and marketer of Rayovac batteries and Remington shavers, said Thursday that its hardware and home improvement group has agreed to buy commercial door and lock manufacturer Tell Manufacturing Inc. of Lititz, Pa. Spectrum's hardware and home improvement group includes the Kwikset, Stanley, Weiser, Baldwin and Pfister brands of residential locks and hardware products. The acquisition of Tell Manufacturing adds commercial products, such as those…