Fixes: U4-5918 Update Underscore.js and also updates our usage of bower with the correct grunt-bower plugin, this massively simplifies bower usage and paves the way to start using bower for all JS components.

src/Umbraco.Web.UI/Umbraco/Views/AuthorizeUpgrade.cshtml

@@ -54,7 +54,7 @@
     </script>
 
     @*And finally we can load in our angular app*@
-    <script type="text/javascript" src="lib/lazyload/lazyload.min.js"></script>
+    <script type="text/javascript" src="lib/rgrove-lazyload/lazyload.js"></script>
     <script type="text/javascript" src="@Url.GetUrlWithCacheBust("Application", "BackOffice")"></script>
 
 </body>

src/Umbraco.Web.UI/Umbraco/js/install.loader.js

@@ -6,7 +6,7 @@ LazyLoad.js( [
       'lib/angular/1.1.5/angular-mobile.min.js',
       'lib/angular/1.1.5/angular-mocks.js',
       'lib/angular/1.1.5/angular-sanitize.min.js',
-      'lib/underscore/underscore.js',
+      'lib/underscore/underscore-min.js',
       'js/umbraco.installer.js'
     ], function () {
         jQuery(document).ready(function () {