Uniqlo is gaining on Zara, H&M, and Gap as the world’s king of casual clothing. But can Tadashi Yanai ride toasty, dry underwear to $50 billion in revenue by 2020? Uniqlo founder Yanai uses design and technology to improve upon classic American sportswear–and now he wants to sell it back to Americans. | Photo by Kareem Black On a drizzly Wednesday afternoon in Tokyo, Tadashi Yanai is hunting for h