update ci and use chrome

.travis.yml

@@ -1,20 +1,24 @@
 ---
+dist: trusty
+
 language: node_js
 node_js:
-  - "4"
+  - "6.11"
 
 sudo: false
 
 cache:
   directories:
     - node_modules
 
+addons:
+  chrome: stable
+
 before_install:
+  - google-chrome-stable --headless --disable-gpu --remote-debugging-port=9222 http://localhost &
   - npm config set spin false
   - npm install -g bower
   - bower --version
-  - npm install phantomjs-prebuilt
-  - node_modules/phantomjs-prebuilt/bin/phantomjs --version
 
 install:
   - npm install