Mess Hall, a new culinary incubator in D.C. more than four years in the making, opened its doors Saturday night for the finals of the Launch Pad, a competition for culinary entrepreneurs. Four finalists—Singer's Significant Meats, Mason Dixie Biscuit Company, FruitCycle and Lulu's Nitrogen Ice Cream—competed for the grand prize, with Mason Dixie ultimately rising to the top...