[chore] Update zuul browser settings (#44)

- Remove deprecated iOS 7.1
- Add Firefox and Microsoft Edge browsers
- Add latest stable Node.js release

Author: darrachequesne

.travis.yml

@@ -1,9 +1,10 @@
 language: node_js
 sudo: false
 node_js:
-  - 0.10
-  - 0.12
-  - 4
+  - '0.10'
+  - '0.12'
+  - '4'
+  - 'node'
 notifications:
   irc: irc.freenode.org##socket.io
 git:
@@ -14,6 +15,8 @@ matrix:
     env: BROWSER_NAME=chrome BROWSER_VERSION=latest
   - node_js: '0.12'
     env: BROWSER_NAME=safari BROWSER_VERSION=latest
+  - node_js: '0.12'
+    env: BROWSER_NAME=firefox BROWSER_VERSION=latest BROWSER_PLATFORM="Windows 10"
   - node_js: '0.12'
     env: BROWSER_NAME=ie BROWSER_VERSION=6
   - node_js: '0.12'
@@ -27,7 +30,7 @@ matrix:
   - node_js: '0.12'
     env: BROWSER_NAME=ie BROWSER_VERSION=latest BROWSER_PLATFORM="Windows 2012"
   - node_js: '0.12'
-    env: BROWSER_NAME=iphone BROWSER_VERSION=7.1
+    env: BROWSER_NAME=microsoftedge BROWSER_VERSION=13 BROWSER_PLATFORM="Windows 10"
   - node_js: '0.12'
     env: BROWSER_NAME=iphone BROWSER_VERSION=8.4
   - node_js: '0.12'