Along with yesterday’s releases of iTunes 10.6 and iOS 5.1 for the iPhone, iPad and iPod touch, Apple also quietly rolled out Apple TV Software Update 5.0. This latest update to Apple’s second-generation set-top box introduces significant new UI enhancements, and paves the way for support of 1080p video content on the new third-generation Apple TV. The update also adds a few additional new features, including support for streaming purchased…