Revert "ignore react for browserify build "
Revert "ignore react for browserify build "

This reverts commit cdca671c98127c90c63d87f667789484dea0e18b.

@threepointone `npm start` actually fails now because of that commit.
Took me a while to discover this because I was working on another branch
all this time.

wilfreddenton/react-motion,keyanzhang/react-motion,souporserious/react-motion,chenglou/react-motion,wilfreddenton/react-motion,pairyo/react-motion,DanielHabib/react-motion,BenoitZugmeyer/preact-motion,danieldunderfelt/react-motion,danieldunderfelt/react-motion,beni55/react-motion,bishopZ/react-motion,dieface/react-motion,threepointone/react-motion,KyleAMathews/react-motion,bishopZ/react-motion,DanielHabib/react-motion,dieface/react-motion,souporserious/react-motion,xyc/react-motion,royriojas/react-motion,YikaJ/react-motion,KyleAMathews/react-motion,threepointone/react-motion,BenoitZugmeyer/preact-motion,mcanthony/react-motion,royriojas/react-motion,oToUC/react-motion,mcanthony/react-motion,pairyo/react-motion,beni55/react-motion,chenglou/react-motion,YikaJ/react-motion,keyanzhang/react-motion,oToUC/react-motion,xyc/react-motion