message: Added missing babel-types to dependencies of polymer-bundler.
diff: "acorn-import-meta": "^0.2.1",
  "babel-generator": "^6.26.1",
  "babel-traverse": "^6.26.0",
  + "babel-types": "^6.26.0",
  "clone": "^2.1.0",
  "command-line-args": "^3.0.1",
  "command-line-usage": "^3.0.3",
  