The “Occupy City Hall” protesters turned the city into a literal toilet, using subway grates as makeshift latrines during their month-long encampment in Lower Manhattan, an MTA supervisor revealed Wednesday as workers cleaned the foul mess. “All the people who were here were going to the bathroom in the vents,” the transit boss said. “They were s–tting and pissing in the vents. They were using this as a facility, as a bathroom. It’s unbelievable what’s in there.” The supervisor was overseeing several workers with the unenviable task of using poles to poke disgusting brown sludge from between the bars of...