Unrestrict version of PolymerElements/iron-list and update it

third_party/polymer/v1_0/components-chromium/iron-list/bower.json

 {
   "name": "iron-list",
   "description": "Displays a virtual, 'infinite' scrolling list of items",
   "keywords": [
     "web-components",
     "polymer",
     "list",
     "virtual-list"
   ],
-  "version": "1.1.7",
+  "version": "1.2.3",
   "homepage": "https://github.com/PolymerElements/iron-list",
   "authors": [
     "The Polymer Authors"
   ],
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/iron-list"
   },
   "main": "iron-list.html",
   "license": "http://polymer.github.io/LICENSE.txt",
   "ignore": [],
   "dependencies": {
     "polymer": "Polymer/polymer#^1.1.0",
-    "iron-resizable-behavior": "polymerelements/iron-resizable-behavior#^1.0.0"
+    "iron-resizable-behavior": "polymerelements/iron-resizable-behavior#^1.0.0",
+    "iron-a11y-keys-behavior": "polymerelements/iron-a11y-keys-behavior#^1.0.0",
+    "iron-scroll-target-behavior": "PolymerElements/iron-scroll-target-behavior#^1.0.0"
   },
   "devDependencies": {
+    "app-layout": "PolymerLabs/app-layout#master",
     "iron-flex-layout": "polymerelements/iron-flex-layout#^1.0.0",
     "iron-component-page": "polymerelements/iron-component-page#^1.0.0",
-    "paper-scroll-header-panel": "polymerelements/paper-scroll-header-panel#^1.0.0",
+    "iron-ajax": "polymerelements/iron-ajax#^1.0.0",
+    "iron-icon": "polymerelements/iron-icon#^1.0.0",
+    "iron-icons": "polymerelements/iron-icons#^1.0.0",
+    "iron-scroll-threshold": "polymerelements/iron-scroll-threshold#^1.0.0",
     "paper-menu": "polymerelements/paper-menu#^1.0.0",
     "paper-item": "polymerelements/paper-item#^1.0.0",
     "paper-icon-button": "polymerelements/paper-icon-button#^1.0.0",
     "paper-button": "polymerelements/paper-button#^1.0.0",
-    "iron-ajax": "polymerelements/iron-ajax#^1.0.0",
-    "iron-icon": "polymerelements/iron-icon#^1.0.0",
-    "iron-icons": "polymerelements/iron-icons#^1.0.0",
     "paper-badge": "polymerelements/paper-badge#^1.0.0",
-    "paper-toolbar": "polymerelements/paper-toolbar#^1.0.0",
     "paper-spinner": "polymerelements/paper-spinner#^1.0.0",
     "test-fixture": "polymerelements/test-fixture#^1.0.0",
     "iron-test-helpers": "polymerelements/iron-test-helpers#^1.0.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.2",
-    "web-component-tester": "polymer/web-component-tester#^3.4.0"
+    "web-component-tester": "^4.0.0"
   }
 }