Improve Travis CI and Appveyor notifications

.travis.yml

@@ -8,3 +8,11 @@ node_js:
   - "iojs"
 before_script:
   - npm install -g electron-prebuilt
+notifications:
+  email: false
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/8b150eaf525c280ec2ac
+    on_success: change
+    on_failure: always
+    on_start: never

appveyor.yml

@@ -28,3 +28,11 @@ test_script:
   - npm --version
   - ps: npm test
   - cmd: npm test
+
+notifications:
+
+  - provider: Webhook
+    url: https://webhooks.gitter.im/e/3d5ed28fa9ae4c25f46f
+    on_build_success: false
+    on_build_failure: true
+    on_build_status_changed: true