By Donny Kwok and Farah Master HONG KONG (Reuters) - Hong Kong police on Monday removed some barricades erected by pro-democracy protesters in the Chinese-controlled city, but said protesters could remain on the streets they have occupied for the past two weeks. At the main protest site, near government offices in the downtown district of Admiralty, scores of student protesters faced off with police who were massing in the area, a Reuters witness said. ...