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

Source/node_modules/core-js/modules/es6.math.trunc.js

@@ -0,0 +1,8 @@
+// 20.2.2.34 Math.trunc(x)
+var $export = require('./_export');
+
+$export($export.S, 'Math', {
+  trunc: function trunc(it) {
+    return (it > 0 ? Math.floor : Math.ceil)(it);
+  }
+});