wrap_inline_tags parameter to convs.Html

For now use `True` by default if `<p>` is allowed and `False` otherwise.

In future we may need to redefine what element (probably with attributes) to wrap with. Then we could use `<p>` if it's allowed, `<div>` if `<p>` is not allowed and `<div>` is. That will cover most cases without I think.
