ActionButton and ActionForm should be referenceable via refs

[nhunzaker]

You should be able to do:

class Test extends React.Component {
  render() {
    return (
      <ActionForm
        ref={form => (this.form = form)}
        action="test"
        send={send}
      />
    )
  }
}

Right now you get a warning about refs in React. I think this is an issue on React's end, but we can circumvent it.