use nvs for CI testing

appveyor.yml

@@ -1,20 +1,25 @@
 environment:
+  UGLIFYJS_TEST_ALL: 1
   matrix:
-    - nodejs_version: "0.10"
-    - nodejs_version: "0.12"
-    - nodejs_version: "4"
-    - nodejs_version: "6"
-    - nodejs_version: "8"
+    - NODEJS_VER: node/0.10
+    - NODEJS_VER: node/0.12
+    - NODEJS_VER: node/4
+    - NODEJS_VER: node/6
+    - NODEJS_VER: node/8
+    - NODEJS_VER: node/latest
 install:
-  - ps: Install-Product node $env:nodejs_version
-  - set UGLIFYJS_TEST_ALL=1
-  - npm install
+  - git clone --branch v1.4.2 --depth 1 https://github.com/jasongin/nvs.git %LOCALAPPDATA%\nvs
+  - set PATH=%LOCALAPPDATA%\nvs;%PATH%
+  - nvs --version
+  - nvs add %NODEJS_VER%
+  - nvs use %NODEJS_VER%
+  - node --version
+  - npm --version --no-update-notifier
+  - npm install --no-optional --no-save --no-update-notifier
 build: off
 cache:
   - tmp
 matrix:
   fast_finish: true
 test_script:
-  - node --version
-  - npm --version
-  - npm test
+  - npm test --no-update-notifier