title: crash after accessing photo library using UIImagePickerController
body: <p>I am having troubles with accessing Photo Library when the button is tapped. Just as usual I am asking if it is accessible. Below is my code </p>
  
  <pre><code>@IBAction func photoLibraryButtonTapped(sender: UIButton) {
  
          if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.PhotoLibrary) {
              let imagePicker = UIImagePickerController()
              imagePicker.delegate = self
              imagePicker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
              imagePicker.allowsEditing = true
              self.presentViewController(imagePicker, animated: true, completion: nil)
          }
      }
  </code></pre>
  
  <p>And here is what Xcode says: </p>
  
  <pre><code>2016-08-08 23:05:11.209 Auyrma[1799:20237892] -[UIViewController photoLibraryButtonTapped:]: unrecognized selector sent to instance 0x7fd3e9d39ed0
  2016-08-08 23:05:11.214 Auyrma[1799:20237892] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIViewController photoLibraryButtonTapped:]: unrecognized selector sent to instance 0x7fd3e9d39ed0'
  *** First throw call stack:
  (
      0   CoreFoundation                      0x0000000113fdcd85 __exceptionPreprocess + 165
      1   libobjc.A.dylib                     0x0000000113a50deb objc_exception_throw + 48
      2   CoreFoundation                      0x0000000113fe5d3d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
      3   CoreFoundation                      0x0000000113f2bcfa ___forwarding___ + 970
      4   CoreFoundation                      0x0000000113f2b8a8 _CF_forwarding_prep_0 + 120
      5   UIKit                               0x00000001124d6a8d -[UIApplication sendAction:to:from:forEvent:] + 92
      6   UIKit                               0x0000000112649e67 -[UIControl sendAction:to:forEvent:] + 67
      7   UIKit                               0x000000011264a143 -[UIControl _sendActionsForEvents:withEvent:] + 327
      8   UIKit                               0x0000000112649263 -[UIControl touchesEnded:withEvent:] + 601
      9   UIKit                               0x000000011254999f -[UIWindow _sendTouchesForEvent:] + 835
      10  UIKit                               0x000000011254a6d4 -[UIWindow sendEvent:] + 865
      11  UIKit                               0x00000001124f5dc6 -[UIApplication sendEvent:] + 263
      12  UIKit                               0x00000001124cf553 _UIApplicationHandleEventQueue + 6660
      13  CoreFoundation                      0x0000000113f02301 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
      14  CoreFoundation                      0x0000000113ef822c __CFRunLoopDoSources0 + 556
      15  CoreFoundation                      0x0000000113ef76e3 __CFRunLoopRun + 867
      16  CoreFoundation                      0x0000000113ef70f8 CFRunLoopRunSpecific + 488
      17  GraphicsServices                    0x00000001164bcad2 GSEventRunModal + 161
      18  UIKit                               0x00000001124d4f09 UIApplicationMain + 171
      19  Auyrma                              0x000000010e1c2d82 main + 114
      20  libdyld.dylib                       0x0000000114e8492d start + 1
      21  ???                                 0x0000000000000001 0x0 + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  </code></pre>