Madison Magazine: Under gray skies on an early Saturday winter morning, locals seek refuge at the Wisconsin Senior Center at 330 W. Mifflin St for the winter farmers’ market. Here, the all-ages crowd is met with the warm, sweet aroma of a home-cooked breakfast, the cheerful sounds of a local bluegrass band and table after colorful table of local produce and food products. Behind one table of sprightly dressed tomatoes and greens stand Mary and Don Uselman. For more than thirty years, the Uselmans have …