def retrieveYFM(text)
      yfm = ""
      text.match(/^(---\s*\n.*?\n?)^(---\s*$\n?)/m) do |md|
        yfm = md.to_s
        text = md.post_match
      end
      return yfm, text
    end
def retrieveYFM(text)
      yfm = ""
      text.match(/^(---\s*\n.*?\n?)^(---\s*$\n?)/m) do |md|
        yfm = md.to_s
        text = md.post_match
      end
      return yfm, text
    end
Retrieve Yaml Front Matter from text.
 Returns [yfm, text]