By Marco Aquino LIMA (Reuters) -Thousands of protesters in Peru, many from the country’s heavily indigenous south, descended on Lima, the capital, on Thursday, angered by a mounting death toll since unrest erupted last month and calling for sweeping change. Police estimated the march at around 3,500 people, but others speculated it attracted more than double that. Rows of police in riot gear faced off against rock-hurling protesters on some streets, and one historic building in the city’s historic center caught fire late on Thursday. The building, on San Martin Plaza, was empty when the massiv…