message: chore(package): update babylon to version 6.18.0
  Closes
diff: "devDependencies": {
  "babel-core": "^6.23.1",
  "babel-preset-es2015": "^6.22.0",
  - "babylon": "~6.17.0",
  + "babylon": "~6.18.0",
  "esprima-fb": "^15001.1001.0-dev-harmony-fb",
  "flow-parser": "^0.55.0",
  "mocha": "~3.5.3",
  