See if appveyor supports node.js 4

Author: lukeapage

appveyor.yml

@@ -3,6 +3,7 @@ environment:
   matrix:
     - nodejs_version: "0.10"
     - nodejs_version: "0.12"
+    - nodejs_version: "4"
 
 # Install scripts. (runs after repo cloning)
 install:
@@ -20,8 +21,7 @@ install:
 # Post-install test scripts.
 test_script:
   # Output useful info for debugging.
-  - node --version
-  - npm --version
+  - node --version && npm --version
   # Run test
   - grunt test