MOSCOW (Reuters) - Prominent Russian opposition leader Sergei Udaltsov, charged with plotting mass disorder in protests last year, was placed under house arrest by a Moscow court on Saturday. The leftist was among several opposition figures charged with riots and violence against police during a protest against President Vladimir Putin last May on the eve of his inauguration for a third presidential term. The Federal Investigative Committee, which answers only to Putin, had barred Udaltsov from travelling freely but said on Friday that he was not complying with that. ...