Boston Globe: For 400 years the sea has been kind to Boston. Maritime trade fed the city`s early economic rise, and countless cod laid down their lives to feed its inhabitants. With the exception of boatloads of occupying redcoats, the Atlantic hasn`t given the city much to complain about. When the area has flooded — as it did this spring — it hasn`t been because of the mighty Atlantic, but the placid Charles. But when Boston`s planning visionaries think about the future, increasingly, it`s the …