BAGHDAD (Reuters) - An Iraqi militant group has produced an elaborate video of what it said were attacks on U.S. troops, in the latest example of the increasingly sophisticated propaganda war being waged by Iraqi insurgents. "The Code of Silence" was posted on the Internet by the Rashedeen Army, thought to be a relatively small Sunni group which has produced videos in the past of attacks it claims to have carried out. At almost an hour in length, it is the longest and most professionally made of recent postings by mainly Sunni militant and insurgent groups fighting the U.S.-backed government....