Merge pull request #2563 from Polymer/bump-iron-doc-viewer

Bump minimum version of iron-doc-viewer to improve anchors.

Author: Arthur Evans

bower.json

@@ -15,7 +15,7 @@
     "app-route": "PolymerElements/app-route#2",
     "iron-ajax": "PolymerElements/iron-ajax#2",
     "iron-collapse": "PolymerElements/iron-collapse#2",
-    "iron-doc-viewer": "PolymerElements/iron-doc-viewer#^3.3.0",
+    "iron-doc-viewer": "PolymerElements/iron-doc-viewer#^3.3.1",
     "iron-flex-layout": "PolymerElements/iron-flex-layout#2",
     "iron-icons": "PolymerElements/iron-icons#2",
     "iron-iconset-svg": "PolymerElements/iron-iconset-svg#2",