upgrade travis config for more targets

Author: mourner

.travis.yml

@@ -2,9 +2,8 @@ language: node_js
 sudo: false
 node_js:
   - "0.10"
-before_install:
-  - npm install -g npm@~1.4.6
+  - "0.12"
+  - "4.1"
 script:
-  - npm install
   - npm test
   - npm run cov