UI plugins API: addSection method

Adds 'addSection' method to UI plugins, which will add a new top-level
section. It follows the same syntax used by the existing sections in
the UI.

ui/plugins/testPlugin/testPlugin.js

@@ -1,7 +1,14 @@
 (function (cloudStack) {
   cloudStack.plugins.testPlugin = function(plugin) {
-    //
-    // Plugin code goes here
-    //
+    plugin.ui.addSection({
+      id: 'testPlugin',
+      title: 'TestPlugin',
+      preFilter: function(args) {
+        return isAdmin();
+      },
+      show: function() {
+        return $('<div>').html('Test plugin section');
+      }
+    });
   };
 }(cloudStack));

ui/scripts/plugins.js

@@ -1,4 +1,13 @@
 (function($, cloudStack, require) {
+  var pluginAPI = {
+    addSection: function(section) {
+      cloudStack.sections[section.id] = section;
+    },
+    extend: function(obj) {
+      $.extend(true, cloudStack, obj);
+    }
+  };
+  
   cloudStack.sections.plugins = {
     title: 'Plugins',
     show: cloudStack.uiCustom.plugins
@@ -15,11 +24,7 @@
 
       // Execute plugin
       cloudStack.plugins[pluginID]({
-        ui: {
-          extend: function(obj) {
-            $.extend(true, cloudStack, obj);
-          }
-        }
+        ui: pluginAPI
       });
     });
   });