The home foreclosure crisis staggered the US economy and led to the Great Recession six years ago. Now — finally -- new housing is under construction. But it's not single-family homes that are going up, but mostly apartment buildings. And Wall Street is going into the rental business. Meantime, many homeowners, especially blacks and Latinos, are still underwater. What does this new form of housing "recovery" reveal about the economy? Does it contain the seeds of another recession?