Implement hooks based approach

[Boosmith]

I was running into issues I think with webpack-dev-server and babel with using hooks. I was getting the dreaded " Uncaught Invariant Violation Invalid hook call". eg. facebook/react#15742
I spent a while looking into this, and trying out react-hot-loader's approach eg. https://github.com/gaearon/react-hot-loader but that ended up introducing a new problem... "Functions are not valid as a React child". eg. gaearon/react-hot-loader#832 But it could be something else entirely...