New York Times: The greenest cars on the market electric vehicles and plug-in hybrids have attracted very few buyers so far. But instead of scaling back, major automakers are eager to bring more battery-powered models to their showrooms. Two of the biggest producers, General Motors and Nissan, served notice at the annual Detroit auto show that they are in the electric-car business for the long haul. G.M., the biggest American automaker, on Tuesday said it would begin production later this year of the Cadillac...