build: support io.js 1.x and 2.x

Author: jonathanong

.travis.yml

@@ -3,6 +3,9 @@ node_js:
   - "0.8"
   - "0.10"
   - "0.12"
+  - "1.0"
+  - "1.8"
+  - "2.0"
 sudo: false
 script: "npm run-script test-travis"
 after_script: "test $TRAVIS_NODE_VERSION = '0.10' && npm install coveralls@2 && cat ./coverage/lcov.info | coveralls"