add comments with estraverse

lib/6to5/util.js

@@ -1,10 +1,13 @@
-var traverse = require("./traverse");
-var acorn    = require("acorn-jsx");
-var path     = require("path");
-var util     = require("util");
-var fs       = require("fs");
-var b        = require("./builders");
-var _        = require("lodash");
+var estraverse = require("estraverse");
+var traverse   = require("./traverse");
+var acorn      = require("acorn-jsx");
+var path       = require("path");
+var util       = require("util");
+var fs         = require("fs");
+var b          = require("./builders");
+var _          = require("lodash");
+
+_.extend(estraverse.VisitorKeys, traverse.VISITOR_KEYS);
 
 exports.inherits = util.inherits;
 
@@ -217,6 +220,8 @@ exports.parse = function (opts, code, callback) {
       ranges:      true
     });
 
+    estraverse.attachComments(ast, comments, tokens);
+
     ast = {
       type: "File",
       program: ast

package.json

@@ -48,7 +48,8 @@
     "source-map-support": "0.2.7",
     "esutils": "1.1.4",
     "acorn-jsx": "https://github.com/sebmck/acorn-jsx/archive/master.tar.gz",
-    "acorn-ast-types": "0.5.3-1"
+    "acorn-ast-types": "0.5.3-1",
+    "estraverse": "^1.7.0"
   },
   "devDependencies": {
     "istanbul": "0.3.2",