Hey guys, I was wondering which parts of the code depend on `babel-polyfill`? Very similar to https://github.com/roylee0704/react-flexbox-grid/issues/49 request. I would very much like not to include `babel-polyfill` in my project, since I don't need it. I'm willing to help out, just let me know where are we using something that `babel-polyfill` covers?