Initial rendered data

[mitermayer]

Can we feed initial content data for initialization? If so, does it accept html as a format?

The reason is that I am seeking to find answers on how to convert an already existing project that was made with tinymce and access a possible migration to draft-js.

[hellendag]

#55 asks about this as well. I think we'll reuse the paste handler to offer some basic support for this.