Massive markup cleanup

<\w+> </\w+>
<\w+></\w+>
<br />
<br/>
<blockquote><em>
 />
   (double space)
alt=""
 style="[^"]*"
 id="_mcePaste"
class="posterous_download_image"
<!--more-->
target="_blank"
&nbsp;
<span style="[^"]*">
</span>