travis: update

.travis.yml

@@ -1,11 +1,12 @@
 language: node_js
-before_install:
-  - "npm install npm -g"
 node_js:
-  - 0.12
+  - "0.12"
-  - 0.10
+  - "4"
-  - iojs
+  - "5"
+matrix:
+  include:
+    - node_js: "4"
+      env: TEST_SUITE=lint
 env:
-  - TEST_SUITE=test
+  - TEST_SUITE=unit
-  - TEST_SUITE=coveralls
+script: npm run-script $TEST_SUITE
-script: "npm run-script $TEST_SUITE"