Cops surrounding Occupy OaklandDemian Bulwa, Chronicle Staff Writer Tuesday, October 25, 2011 (10-25) 04:48 PDT OAKLAND -- Oakland police are arriving this morning in force, apparently preparing to remove hundreds of people from a plaza outside City Hall, two weeks after the protesters began building an intricate encampment as part of the Occupy Wall Street movement against corporate greed and economic inequality. Officers in riot helmets began arriving at Frank Ogawa Plaza at the corner of 14th Street and Broadway at 4:45 a.m. and formed a line in the street adjacent to the plaza. Some protesters began shouting, "Cops, go...