Update travis config to run on multiple versions of webpack

Author: peternewnham

.travis.yml

@@ -1,9 +1,17 @@
 language: node_js
 
 node_js:
+  - 7
   - 6
   - 5
   - 4
 
+env:
+  - WEBPACK_VERSION=2.2.0-rc.4
+  - WEBPACK_VERSION=1
+
 matrix:
   fast_finish: true
+
+before_script:
+  - npm install webpack@$WEBPACK_VERSION

package.json

@@ -29,8 +29,7 @@
     "eslint": "^3.0.0",
     "eslint-friendly-formatter": "^2.0.4",
     "npmpub": "^3.0.1",
-    "tape": "^4.0.0",
-    "webpack": "^1.8.4"
+    "webpack": "^2.2.0-rc.4"
   },
   "scripts": {
     "lint": "eslint .",