parse_html and custom components

[arechnitzer]

I'm trying to make some custom components and I'd like to get them to work with the parse_html function. I've tried added the @jp.parse_dict decorator, but without success.

If I wanted to get your "MyAlert" component from the docs to work as a tag recognised by jp.parse_html, how would I need to adapt it?

[elimintz]

Please see #287