Otterbox has posted a teaser page and video for its upcoming Armor Series case for the iPhone 4 and iPhone 4S. Billed by the long-time case maker as “the toughest case we’ve ever built”, the Armor Series promises to be drop proof, dust proof, crush proof, and waterproof; a promotional video posted on the teaser page makes mention of a thermoplastic shell—precision fit to within 3/1000 of an inch—and a medical-grade…