[Fix bug 1033298] Enable markdown support in new vouching interface.

How about
```
      <form action="{{ url('phonebook:profile_view', shown_user.username) }}" method="POST"
            id="vouch-form">
        {{ csrf() }}
        {{ vouch_form }}
        {% trans url='http://daringfireball.net/projects/markdown/syntax' %}
          Use <a href="{{ url }}">Markdown</a> for bold, italic, lists and links.
        {% endtrans %}
        {{ _('Characters remaining:') }} 
        <span class="character-countdown">500</span>
        <div id="vouch-submit">
          <button class="button" type="submit"><i class="icon-key"></i>
            {% trans name=profile.display_name %}
              Vouch for {{ name }}
            {% endtrans %}
          </button>
        </div>
      </form>
```

which brings the "Markdown" text right bellow the textbox. Currently it feels like it's not referring to the textbox

![screenshot-127 0 0 1 8000 2014-07-03 11-44-35](https://cloud.githubusercontent.com/assets/584352/3467250/4e6211e0-028e-11e4-8343-f86ea21c7045.png)