Exxon Mobil sees reversal in North American oil trade

    By Jim Lander     The spreading oil and gas boom is leading North America toward energy self-sufficiency.     And in the not-too-distant future, the continent will be a net exporter of both natural gas and oil, Exxon Mobil Corp. predicted Wednesday in its 2013 Energy Outlook.     “This competitive energy supply provides a strong foundation for...