use n instead of nvm for working iojs support

.travis.yml

@@ -1,14 +1,30 @@
-language: node_js
-node_js:
-  - "0.10"
-branches:
-  only:
-    - master
-notifications:
-  email:
-    - [email protected]
-script: npm test
+language: c
 
 before_install:
-  - npm install -g npm@latest
+  - rm -rf ~/.nvm
+  - wget https://raw.githubusercontent.com/visionmedia/n/master/bin/n -qO n
+  - chmod +x n
+  - sudo cp n /usr/local/bin/n
+  - sudo chmod -R a+xw /usr/local
+  - n --version
+
+script:
+  - n 0.10
+  - node -v; which node; npm -v; which npm
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
+
+  - n latest
+  - node -v; which node; npm -v; which npm
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
 
+  - n io latest
+  - iojs -v; which iojs; npm -v; which npm
+  - JOBS=max npm install
+  - npm test
+
+notifications:
+  email:
+    - [email protected]
+    - [email protected]