Support for code block, blockquote etc.

Hi,

Fiest of all thank you for this project it really looks fantastic and would solve a problem in my current application.

Could you please elaborate what is currently stopping the implementation of the types stated in the readme?

As far as I can see these types are supported from Down and there even exist commented code for some of these types?

I would really like to understand the current issue with these to make sure whether this library could be useful for my project or not.

Kind regards,
David

Provide feedback