WASHINGTON (AP) -- With jobs and federal aid at stake, U.S. cities are lining up to contest their 2010 census counts as too low. A decade ago, there were 1,200 challenges filed by cities, towns and counties. The U.S. Conference of Mayors is predicting a big jump in that number, due in part to tighter budgets that make local officials more sensitive to potential drop-offs in federal money for Medicaid and other programs....