First support for md extensions; Package all needed dependencies in the repo

Source/node_modules/core-js/modules/es7.array.includes.js

@@ -0,0 +1,12 @@
+'use strict';
+// https://github.com/tc39/Array.prototype.includes
+var $export = require('./_export');
+var $includes = require('./_array-includes')(true);
+
+$export($export.P, 'Array', {
+  includes: function includes(el /* , fromIndex = 0 */) {
+    return $includes(this, el, arguments.length > 1 ? arguments[1] : undefined);
+  }
+});
+
+require('./_add-to-unscopables')('includes');