Merge branch 'master' into heuristics

extract_features.js

+return (function() {
+  function hasOGArticle() {
+    var elems = document.head.querySelectorAll(
+        'meta[property="og:type"],meta[name="og:type"]');
+    for (var i in elems) {
+      if (elems[i].content && elems[i].content.toUpperCase() == 'ARTICLE') {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  var body = document.body;
+  return {
+     'opengraph': hasOGArticle(),
+     'url': document.location.href,
+     'numElements': body.querySelectorAll('*').length,
+     'numAnchors': body.querySelectorAll('a').length,
+     'numForms': body.querySelectorAll('form').length,
+     'innerText': body.innerText,
+     'textContent': body.textContent,
+     'innerHTML': body.innerHTML,
+  }
+})()