Celebrities such as Justin Bieber, Russell Brand and Lenny Kravitz have all been spotted wearing leggings, while such fashion stores as Uniqlo, Barneys and Nordstrom are selling tights for men.The bad news is they are catching on, and their success in New York is seen as an indication they will also prove popular elsewhere.They are expected to follow on from the trend for "skinny jeans" on men, wh