By Michael S. Derby (Reuters) -Overall U.S. household debt levels increased modestly in the third quarter as borrowing in some form of trouble stabilized and student loan woes increased, the New York Federal Reserve said on Wednesday. As part of its latest report on borrowing in the economy, the regional Fed bank said overall borrowing for the third quarter rose 1%, or $197 billion, from the second quarter, to$18.6 trillion. From a year ago, total borrowing was up $642 billion. Most categories of borro ...