Migration to yarn for CI (jhen0409#53)

* Add yarn lockfile & update travis

* Update appveyor.yml

.travis.yml

@@ -2,7 +2,12 @@ sudo: required
 dist: trusty
 language: node_js
 node_js:
-  - "4"
+  - "6"
+  - "7"
+cache:
+  directories:
+    - $HOME/.yarn-cache
+    - node_modules
 env:
   - CXX=g++-4.8
 addons:
@@ -16,15 +21,16 @@ addons:
 
 install:
   - "/sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1280x1024x16"
-  - npm install
+  - npm install -g yarn
+  - yarn install
 
 before_script:
   - export DISPLAY=:99.0
   - sh -e /etc/init.d/xvfb start &
   - sleep 3
 
 script:
-  - npm run lint
-  - npm test
-  - npm run build
-  - npm run test-e2e
+  - yarn run lint
+  - yarn test
+  - yarn run build
+  - yarn run test-e2e

appveyor.yml

@@ -1,18 +1,21 @@
 environment:
   matrix:
-    - nodejs_version: '4'
+    - nodejs_version: '6'
+    - nodejs_version: '7'
+
+cache:
+  - "%LOCALAPPDATA%/Yarn"
+  - node_modules
 
 install:
   - ps: Install-Product node $env:nodejs_version
-  - npm -g install npm@2
-  - set PATH=%APPDATA%\npm;%PATH%
-  - npm install --msvs_version=2013
+  - yarn install
 
 test_script:
   - node --version
-  - npm --version
-  - cmd: npm run lint
-  - cmd: npm test
-  - cmd: npm run build
+  - yarn --version
+  - yarn run lint
+  - yarn test
+  - yarn run build
 
 build: off