Improved response to power state changes in Switchboard (#191)

This resolves a problem if the user turns off Bluetooth in Switchboard,
the Wingpanel indicator would immediately turn it back on (and vice
versa).

src/Services/Manager.vala

@@ -115,7 +115,7 @@ public class BluetoothIndicator.Services.ObjectManager : Object {
             ((DBusProxy) adapter).g_properties_changed.connect ((changed, invalid) => {
                 var powered = changed.lookup_value ("Powered", new VariantType ("b"));
                 if (powered != null) {
-                    set_last_state.begin ();
+                    set_global_state.begin (powered.get_boolean ());
                 }
             });
         }
@@ -217,6 +217,7 @@ public class BluetoothIndicator.Services.ObjectManager : Object {
         }
 
         settings.set_boolean ("bluetooth-enabled", state);
+        check_global_state ();
     }
 
     public async void set_last_state () {