Update Popper.js to v2.x

Created by: NemoDima

Hello

Could you please plan the process of updating Popper.js to ver2.0.0. X ? As a result, a lot of bugs will be fixed: https://github.com/popperjs/popper.js/labels/Fixed%20in%20v2 One of them is my https://github.com/popperjs/popper.js/issues/835

I'll be appreciated. Regards, Dmytro