various: update for gnome-shell changes

The panel changed the way it builds the buttons outside the system
status area.
- Update alternative-status-menu to the new way of accessing panel
  contents.
- Update apps-menu to the new way of adding items to the panel.
- Move places-menu to the left now that it is possible without hacks.

extensions/alternative-status-menu/extension.js

@@ -48,7 +48,7 @@ function init(metadata) {
 }
 
 function enable() {
-    let statusMenu = Main.panel._statusArea.userMenu;
+    let statusMenu = Main.panel.statusArea.userMenu;
 
     settings = Convenience.getSettings();
 
@@ -96,7 +96,7 @@ function enable() {
 }
 
 function disable() {
-    let statusMenu = Main.panel._statusArea.userMenu;
+    let statusMenu = Main.panel.statusArea.userMenu;
 
     let children = statusMenu.menu._getMenuItems();
     let index = children.length;

extensions/apps-menu/extension.js

@@ -99,9 +99,7 @@ let appsMenuButton;
 
 function enable() {
     appsMenuButton = new ApplicationsButton();
-    Main.panel._leftBox.insert_child_at_index(appsMenuButton.actor, 1);
-    Main.panel._leftBox.child_set(appsMenuButton.actor, { y_fill : true } );
-    Main.panel._menus.addMenu(appsMenuButton.menu);
+    Main.panel.addToStatusArea('apps-menu', appsMenuButton, 1, 'left');
 }
 
 function disable() {

extensions/places-menu/extension.js

@@ -162,7 +162,7 @@ let _indicator;
 
 function enable() {
     _indicator = new PlacesMenu;
-    Main.panel.addToStatusArea('places-menu', _indicator);
+    Main.panel.addToStatusArea('places-menu', _indicator, 1, 'left');
 }
 
 function disable() {