Winter DreamsSOME of the caddies were poor as sin and lived in one room houses with a neurasthenic cow in the front yard, but Dexter Green's father owned the second best grocery store in Black Bearthe best one was "The Hub," patronized by the wealthy people from Sherry Islandand Dexter caddied on ly for pocket money. IN the fall when the days became crisp and gray, and the long Minnesota winter shut down like the white lid of a box, Dexter's skis moved over the