Fifty years ago, two kids from Seattle flipped the tech industry on its head.While all the big brains in personal computing were focused on machines — “microcomputer” hardware — Bill Gates and Paul Allen were thinking about the technology that made the machines go: software. That idea, planted by Allen at Gates’ Boston-area apartment, became the opening verse of Microsoft’s epic.Gates and Allen launched “Micro-Soft” on April 4, 1975, out of a small office in a strip mall in Albuquerque, N.M., th...