By Leah Schnurr NEW YORK (Reuters) - After a strong start to the year, the world's largest economy is set to slow as some of the effects of government spending cuts take hold, likely leaving the central bank's extraordinary stimulus in place into at least 2014. Still, the labor market is expected to continue healing this year, even after last month's disappointingly weak job gains, and the housing recovery should gain momentum. Both should help keep the economy from cooling too much. ...