Add shortcode for Whisper.sh

[danielbachhuber]

It should reverse:

<div class='whisper-embed' data-wid='05023b6b8271b759019944d046011887fa2ea3' data-footer='false'><a href='http://whisper.sh/whisper/05023b6b8271b759019944d046011887fa2ea3' target='_blank'><img src='http://embed.whisper.sh/whisper.sh/05023b6b8271b759019944d046011887fa2ea3.jpg' alt='I&#39;m a petite female who wears a hijab and most people I meet tell me I look so sweet and innocent. In reality I cuss like a sailor, don&#39;t give two shits when people are judgmental, and am insanely attracted to guys with tattoos and piercings.' style='width:100%;max-width:640px;border:none;' /></a></div><script src='http://cdn-web.whisper.sh/embed/v1' async></script>