Support embedding collections/searches

[eyeseast]

Here's what the embed code looks like:

<div id="DC-search-group-homicide-watch" class="DC-search-container"></div>
<script src="//s3.amazonaws.com/s3.documentcloud.org/embed/loader.js"></script>
<script>
  dc.embed.load('http://www.documentcloud.org/search/embed/', {
    q: "group: homicide-watch",
    container: "#DC-search-group-homicide-watch",
    title: "Homicide Watch DC",
    order: "title",
    per_page: 12,
    search_bar: true,
    organization: 170
  });
</script>

[reefdog]

Renaming this to "Support embedding collections/searches", since it's actually going to use the same shortcode.