By Mia Shanley STOCKHOLM (Reuters) - Community patrols and a beefed-up police presence helped to calm violence around Stockholm overnight on Saturday but 20 to 30 cars were still torched in poor immigrant suburbs and serious incidents were reported outside the capital for the first time. The rioting in Stockholm abated after a week of masked youths vandalizing schools and police stations, setting cars alight and hurling stones at firefighters, police said. "It was much calmer - rocks weren't being thrown at police or firefighters - and that's a sign that it's calmer. ...