title: Passing in memory html file to pdfkit
body: <p>I just downloaded a website with python</p>
  
  <pre><code>p =urllib2.build_opener(urllib2.HTTPCookieProcessor).open('http://www.google.com')
  html_content = p.read()
  </code></pre>
  
  <p>And now I want to write it to a pdf file:</p>
  
  <pre><code>pdfkit.from_file(??????,'test.pdf')
  </code></pre>
  
  <p>But how do I pass the html_content in the function?
  It expects a file, but I don't want to save the file first as a html. Is there a way to pass the fetched html_content in the pdfkit.from_file function?</p>
  
  <p>Note: I don't wish to use .from_url, I first want to fetch the page using urllib2.</p>