Cold weather and the housing slowdown put a damper on nationwide construction jobs in February according to the Associated General Contractors of America, but nonresidential segments should rebound this month.  February included a week of ice storms across much of the U.S. whereas January had an exceptionally balmy week.  As a result, some contractors may have started jobs in January that normally would have been postponed until later in the spring, then postponed hiring during the freeze.  One sign that nonresidential construction will resume growth is the fact that architectural and engineering firms have seen a 5 percent increase in job growth over the past year, and their work turns into construction within a few months.  Meanwhile, nonresidential construction spending is up 15 percent over last January.  The AGC concludes that nonresidential construction will be healthy through 2007, and probably beyond.