title: Insert LoginViewController (UIViewController) before UINavigationController throws exception
body: <p>We've developed an application with UINavigationController where the user can also switch between different 'Master-Detail' views. Now we'd like to insert a LoginViewController before UINavigationController and push NavigationController from it if Login is successful. </p>
  
  <p>LoginViewController.m:</p>
  
  <pre><code>@implementation LoginViewController
  
  - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
  {
      self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
      if (self) {
  
  }
  return self;
  }
  
  - (void)viewDidLoad
  {
  
  UIImage *background = [UIImage imageNamed:@"LoginViewBG.png"];
  UIImageView *backgroundView = [[UIImageView alloc] initWithImage:background];
  
  [self.view addSubview: backgroundView];
  
  [super viewDidLoad];
  
  
  }
  
  - (void)didReceiveMemoryWarning
  {
  [super didReceiveMemoryWarning];
  
  }
  
  -(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
  {
  
   }
  - (IBAction)loginButtonPress:(id)sender {
  [self performSegueWithIdentifier:@"login_success" sender:self];
  }
  
  - (IBAction)backgroundTap:(id)sender {
  [self.view endEditing:YES];
  }
  
  -(BOOL)textFieldShouldReturn:(UITextField *)textField
  {
  [textField resignFirstResponder];
   return YES;
  }
  </code></pre>
  
  <p>The Exception Thrown : </p>
  
  <pre><code>2014-08-19 11:01:31.337 iRehberBeta[24847:60b] -[LoginViewController navigationBar]:   unrecognized selector sent to instance 0xc0816c0
  2014-08-19 11:01:31.363 iRehberBeta[24847:60b] *** Terminating app due to uncaught exception  'NSInvalidArgumentException', reason: '-[LoginViewController navigationBar]: unrecognized  selector sent to instance 0xc0816c0'
  *** First throw call stack: 
  ( 
  0   CoreFoundation                      0x051111e4 __exceptionPreprocess + 180
  1   libobjc.A.dylib                     0x047c38e5 objc_exception_throw + 44
  2   CoreFoundation                      0x051ae243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
  3   CoreFoundation                      0x0510150b ___forwarding___ + 1019
  4   CoreFoundation                      0x051010ee _CF_forwarding_prep_0 + 14
  5   iRehberBeta                         0x00025ac1 -[AppDelegate application:didFinishLaunchingWithOptions:] + 193
  6   UIKit                               0x0347d14f -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 309
  7   UIKit                               0x0347daa1 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1810
  8   UIKit                               0x03482667 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
  9   UIKit                               0x03496f92 -[UIApplication handleEvent:withNewEvent:] + 3517
  10  UIKit                               0x03497555 -[UIApplication sendEvent:] + 85
  11  UIKit                               0x03484250 _UIApplicationHandleEvent + 683
  12  GraphicsServices                    0x05c03f02 _PurpleEventCallback + 776
  13  GraphicsServices                    0x05c03a0d PurpleEventCallback + 46
  14  CoreFoundation                      0x0508cca5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 53
  15  CoreFoundation                      0x0508c9db __CFRunLoopDoSource1 + 523
  16  CoreFoundation                      0x050b768c __CFRunLoopRun + 2156
  17  CoreFoundation                      0x050b69d3 CFRunLoopRunSpecific + 467
  18  CoreFoundation                      0x050b67eb CFRunLoopRunInMode + 123
  19  UIKit                               0x03481d9c -[UIApplication _run] + 840
  20  UIKit                               0x03483f9b UIApplicationMain + 1225
  21  iRehberBeta                         0x00026bfd main + 141
  22  libdyld.dylib                       0x04ce6701 start + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  (lldb) 
  </code></pre>