Add list of currently supported / not supported material components to the readme

[pbadeer]

Would be super handy, open to suggestions or alternatives :)

[petegivens]

good suggestion @pbadeer. We hope to improve our documentation drastically in the coming weeks and months (and we would welcome any PRs). In the meantime, if you build the project locally and open it in your browser at localhost:8081, you'll see a list of all of the currently supported components.