Tupperware wants to be where the cool kids play. The 76-year-old brand is on a quest to grab the attention of Millennials and Gen Zers, and wants to become as relevant in their everyday lives as it was for their grandmas and moms. But to get on their radar, Tupperware has to show up in ways that matter to younger shoppers. That means shedding its throwback to its Mad Men-era image, and positioning Tupperware products as buzz-worthy, high-utility and with an environmentally-friendly purpose. That repositioning is already underway for Tupperware. Stock Market Today: Stocks Fall for Fourth Consecutive Session In…