message: feat(windows): Use msvs 2015 to build on appveyor
diff: # http://www.appveyor.com/docs/appveyor-yml
  # mostly copied from nan appveyor.yml
  +os: Visual Studio 2015
  +
  environment:
  DEBUG: "node-libcurl"
  NODE_LIBCURL_GITHUB_TOKEN:
  @@ -38,7 +40,7 @@ install:
  build_script:
  - node tools\retrieve-win-deps.js
  - - npm install --build-from-source --msvs_version=2013 --loglevel=http
  + - npm install --build-from-source --msvs_version=2015 --loglevel=http
  # Post-install test scripts.
  test_script:
  