Kindle Fire HDX comes with free Mayday tech support

\’We don\’t need people to be on the upgrade treadmill. If I see people using a 5-year-old Kindle, I\’m delighted,\’ Bezos says.Of course, he\’d be equally delighted to sell you new hardware. Today Amazon unfurls a potentially disruptive tech-support feature — Mayday — that\’s aimed at rescuing people …