After the Groundhog Day Thaw is over next week, weather history says these should be some of the coldest days of winter. In many years, however, crocus, daffodil and tulip foliage emerges. Garlic planted in November has sometimes pushed out of the ground; cloves set in early October are already several inches high. Sometimes more than half of the pussy willows have opened. All along the 40th Parallel, people are getting ready to tap maples for sap. Signs are accumulating, spring a matter of