add matrix to .travis.yml

.travis.yml

@@ -1,15 +1,19 @@
 language: node_js
 before_install:
-  - "npm install npm -g"
+  - npm install npm -g
 node_js:
-  - "4.0.0"
-  - "io.js"
-  - "0.12"
-  - "0.10"
+  - 5
+  - 4
+  - io.js
+  - 0.12
+  - 0.10
+matrix:
+  include:
+    - node_js: 4
+      env: TEST_SUITE=standard
 env:
   - TEST_SUITE=coverage
   - TEST_SUITE=integration
-  - TEST_SUITE=standard
   - TEST_SUITE=unit
-script: "npm run-script $TEST_SUITE"
+script: npm run-script $TEST_SUITE
 sudo: false