Add logout functionality.

Mobile Buy SDK Sample Apps/Sample App Customers/Sample App Customers/Base.lproj/Main.storyboard

@@ -290,7 +290,11 @@
                         </constraints>
                     </view>
                     <navigationItem key="navigationItem" title="Orders" id="QJf-qx-qvw">
-                        <barButtonItem key="leftBarButtonItem" title="Logout" id="Iio-Wf-I5q"/>
+                        <barButtonItem key="leftBarButtonItem" title="Logout" id="Iio-Wf-I5q">
+                            <connections>
+                                <action selector="logoutAction:" destination="gsn-tk-U20" id="7BT-DV-iXS"/>
+                            </connections>
+                        </barButtonItem>
                     </navigationItem>
                     <connections>
                         <outlet property="tableView" destination="0Fn-mj-l5t" id="ZFj-eI-hKE"/>

Mobile Buy SDK Sample Apps/Sample App Customers/Sample App Customers/OrdersViewController.swift

@@ -59,6 +59,13 @@ class OrdersViewController: UIViewController {
             }
         }
     }
+    
+    // ----------------------------------
+    //  MARK: - UI Actions -
+    //
+    @IBAction func logoutAction(sender: AnyObject) {
+        self.navigationController?.popViewControllerAnimated(true)
+    }
 }
 
 // ----------------------------------