appveyor node matrix update

Author: todbot

appveyor.yml

@@ -4,10 +4,13 @@ environment:
     secure: VYJPed/ilAHFpd7S0zW/C2U1jVqayW5QFBitwBqralJlKlgAPW6n1L1VUIOJswiW
 
   matrix:
+  - nodejs_version: "4"
   - nodejs_version: "6"
+  - nodejs_version: "7"
 
 platform:
 - x64
+- x86
 
 install:
 - ps: Update-NodeJsInstallation (Get-NodeJsLatestBuild $env:nodejs_version) $env:platform;