Replaces yepnope.js with lazyload.js

Solves the caching and multi-load of the same file problems - adds a bit
of promise-based loading logic ontop of ll.js to ensure order and count

src/Umbraco.Web/UI/JavaScript/Main.js

@@ -1,22 +1,8 @@
-"##JsNoCache##"
-yepnope({
-    load: [
-         'lib/jquery/jquery-2.0.3.min.js',
-         'lib/angular/1.1.5/angular.min.js',
-         'lib/underscore/underscore.js',
-    ],
-    complete: function () {
-        yepnope({
-            load: "##JsInitialize##",
-            complete: function () {
+LazyLoad.js("##JsInitialize##", function () {
+    //we need to set the legacy UmbClientMgr path
+    UmbClientMgr.setUmbracoPath('"##UmbracoPath##"');
 
-                //we need to set the legacy UmbClientMgr path
-                UmbClientMgr.setUmbracoPath('"##UmbracoPath##"');
-
-                jQuery(document).ready(function () {
-                    angular.bootstrap(document, ['umbraco']);
-                });
-            }
-        });
-    }
+    jQuery(document).ready(function () {
+        angular.bootstrap(document, ['umbraco']);
+    });
 });