fix(ci): correctly report appveyor failures

Author: filipesilva

.appveyor.yml

@@ -14,6 +14,8 @@ test_script:
   - node --version
   - npm --version
   - npm test
+  - echo ---------------- Exit Code is %errorlevel%
   - node tests\e2e_runner.js
+  - echo ---------------- Exit Code is %errorlevel%
 
 build: off