Update travis.yml for newer versions and drop 0.10.

Author: STRML

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
 node_js:
-  - "0.10"
   - "0.12"
+  - "4.0"
 before_script:
   - export DISPLAY=:99.0
   - sh -e /etc/init.d/xvfb start