use n instead of nvm for iojs support on native modules

.travis.yml

@@ -1,23 +1,51 @@
-language: node_js
-node_js:
-  - "0.8"
-  - "0.10"
+language: c
+
+before_install:
+  - 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
+
 branches:
   only:
     - master
+
+script:
+  - n io latest
+  - iojs -v; npm -v;
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
+
+  - n latest
+  - node -v; npm -v;
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
+
+  - n 0.10
+  - node -v; npm -v;
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
+
+  - n 0.8
+  - npm install npm -g
+  - node -v; npm -v;
+  - JOBS=max npm install
+  - npm test && rm -rf node_modules/
+
 notifications:
   email:
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
-    - [email protected]
+    - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
     - [email protected]
-script: npm test