Added Appveyor build support

Author: thecoder75

appveyor.yml

@@ -0,0 +1,21 @@
+os: unstable
+cache:
+  - node_modules
+environment:
+  GH_TOKEN:
+      secure: ruXayOUgryDqMg8KBrkEVzK3WZCvh+nJq1ZVA8NRylHdeQQDQO44wfyBf0Bi9ZUt
+  matrix:
+    - nodejs_version: 8
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - set CI=true
+  - cd src
+  - yarn install
+matrix:
+  fast_finish: true
+build: off
+version: '{branch}-{build}'
+shallow_clone: true
+clone_depth: 1
+test_script:
+  - yarn dist-appveyor