NEW YORK (AP) - If a time traveler from a hundred years ago were to visit a home today, much of the technology would be completely alien. The television, cordless phone and computer would probably leave him flabbergasted. But on seeing a light bulb, he might say, "Ah! Here's something I recognize. A few of those grace my home, too." If the visitor comes back in 15 years, the fruit of Thomas Edison's bright idea may be gone. The likely replacement: light-emitting diodes, or LEDs. LED lamps were unthinkable until the technology cleared a major hurdle just a dozen years...