Update Travis config

Author: taion

.travis.yml

@@ -1,18 +1,14 @@
 sudo: false
 language: node_js
 node_js:
-- 4
+  - stable
 cache:
   directories:
     - node_modules
-notifications:
-  webhooks:
-    urls:
-      - https://webhooks.gitter.im/e/006ca15725d53eab80e5
-    on_success: always
-    on_failure: always
-    on_start: false
 before_install:
   - export CHROME_BIN=chromium-browser
   - export DISPLAY=:99.0
   - sh -e /etc/init.d/xvfb start
+branches:
+  only:
+    - master