add programatic way to specify pull quotes

[bcoe]

Based on @jameswomack's suggestion, it would be slick if we could programmatically specify pull quotes.

[jameswomack]

Some version of the below could be adapted to suit our needs.

// Forgoing jQuery, using https://gist.github.com/jameswomack/d3b536298687e3264810

var articles = $('[itemprop=articleBody]');
articles.forEach(function pullQuotesInArticle(article){
  // Linguistic analysis could be used to forgo placeholders
  // but this solution is more flexible in terms of design
  var placeholderEls = article.$('section[for=pullquote]');
  var placeHolderCount = placeholderEls.length;

  // Only pull as many quotes as there are placeholders
  var quoteEls = article.$('[data-pullquote]').slice(0, placeHolderCount);
  quoteEls.forEach(function(quoteEl, index){
    placeholderEls[index].appendChild(quoteEl);
  });
});

<div itemprop="articleBody" class="article-body">
<section for="pullquote"></section><!-- a pullquote placeholder -->
<p><span data-pullquote>Polyglot Weekly grows from the question, <em>"what would get me blogging more often?"</em></span>I came up with a list of answers:</p> ...
<p>I can't wait to see what comes of this,</p>
<p>— Ben.</p>
</div>

[bcoe]

I like the simplicity of simply having a pull-quote section.

We could use cheerio to populate the sections prior to writing the article to disk:

https://github.com/polyglotweekly/articleify/blob/master/lib/article.js#L104