Calling it the “the biggest advancement in the history of iPhone,” Tim Cook today introduced the new iPhone 6 and iPhone 6 Plus, which are the same devices previously leaked. They are glass-fronted, anodized aluminum backs, with stainless steel Apple logos. The new iPhone 6 comes in two screen sizes—4.7” and 5.5”—which Apple is calling “Retina HD displays,” “new in every way,” and SRGB color-accurate.…