Americans continued earning more and spending more in February, according to a government report released yesterday, adding to other signs that the economy is recovering steadily from last year's slump. The Commerce Department reported that personal income rose 0.6 percent in February, the fourth consecutive month of increases. And consumers spent 0.6 percent more in February, continuing a three-month rise. Consumers continued spending at a healthy pace through most of last year, despite layoffs, uncertainty and the Sept. 11 terrorist attacks -- a key reason the recession was the mildest on record, economists say. But much of the strength of...