Beverly Citizen: The little boy holding the sign looked so determined to have us understand how serious this is. Six-year-old Louis had come from Milton with his mom and sister to join protestors in front of the Salem coal-fired power plant. Sunday, March 1, was a cold, snowy Nor`easter storm day in New England, but Louis didn`t seem to mind. It appeared as if Louis felt like he had a job to do — telling us adults that we better pay attention to the damage we were doing. I came to the protest out of …