Add note in README that it doesn't work with HTML components

[xaviervia]

Because it doesn't, since there is no component reference to pass down to the Materialize component.

I don't see an easy solution for this, but on the other hand I also don't see much value in providing support. Writing a custom wrapper is trivial and probably a good idea since handlers such as onClick need to be sanitized not to send back circular reference object structures before being used with React Entanglement.

[pirelenito]

Exactly, we need a "Caveats" section in the documentation.