Disable wpautop on embeds

When some embeds are inserted into the_content by WP_Embed, wpautop wraps them in <p> tags. This behavior is not ideal. The reason for this is that some embeds, like YouTube, are not wrapped in a block element. The WP_Embed class has a filter, embed_handler_html, which can be used to override this behavior by wrapping the embed in a block element.