Include iron-component-page in devDependencies

Fix Polymer#3645

Author: jorgecasar

bower.json

@@ -28,7 +28,8 @@
     "webcomponentsjs": "^0.7.20"
   },
   "devDependencies": {
-    "web-component-tester": "*"
+    "web-component-tester": "*",
+    "iron-component-page": "polymerElements/iron-component-page#^1.1.6"
   },
   "private": true
 }