message: fix TravisCI config
diff: -udo: false
  +sudo: false
  language: node_js
  +
  node_js:
  - 8
  - - 6
  +
  cache:
  yarn: true
  directories:
  - node_modules
  +
  +before_install:
  + - export CHROME_BIN=/usr/bin/google-chrome
  + - export DISPLAY=:99.0
  + - sh -e /etc/init.d/xvfb start
  