Upgrade webpack

Author: jakezatecky

package.json

@@ -55,7 +55,7 @@
     "react-addons-test-utils": "^15.4.2",
     "react-dom": "^15.4.2",
     "react-test-renderer": "^15.5.4",
-    "webpack": "^2.2.1",
+    "webpack": "^3.0.0",
     "webpack-stream": "^3.2.0"
   },
   "dependencies": {