International Herald Tribune: Everyone knows what blue-collar and white-collar jobs are, but now a job of another hue – green – has entered the lexicon. U.S. presidential candidates talk about the promise of green-collar jobs – an economy with millions of workers installing solar panels, weatherizing homes, brewing biofuels, building hybrid cars and erecting giant wind turbines. Labor unions view these new jobs as replacements for positions lost to overseas manufacturing and outsourcing. Urban groups view training …