Every fall for the past 31 years, Russell Belding has watched as mobs of tourists board buses outside his office at the Department of Motor Vehicles in Montpelier, Vt.He knows they come seeking the brilliant hues of the autumn leaves for which his state is famous. But to Belding, 53, who has a red-green color vision defect, the marvelous views are just meh.“I’m in Vermont and every October I c