By Daniela Perez Athletes and observers around the world paid homage to the superstar as the news broke. Roger Federer, a 20-time Grand Slam champion and tennis icon, announced Thursday he will retire from tennis following the Laver Cup in London. “I have played more than 1,500 matches over 24 years,” he said in a video posted to Twitter. “Tennis has treated me more generously than I ever would have dreamt, and now I must recognize when it is time to end my competitive career. The Laver Cup next week in London will be my final ATP event. I will play more tennis in the future, of course, but ju…