Most of Hong Kong and other parts of southern China ground to a near standstill Friday, with classes and flights cancelled as powerful Typhoon Saola passed along the coast. Many workers stayed at home and students in various cities saw the start of their school year postponed to next week. Trading on Hong Kong's stock market was suspended and hundreds of people were stranded at the airport after about 460 flights were cancelled in the key regional business and travel hub. Rail authorities in mainland China halted all trains entering or leaving Guangdong province from Friday night to Saturday evening,...