No event for Facebook login failure on Windows 8

[WheretIB]

If Facebook login is unsuccessful (throws an exception), LoginWithBehavior function calls internal OnSessionStateChanged event, but does not call public OnFacebookAuthenticationFinished event to report the condition to the application:

https://github.com/facebook-csharp-sdk/facebook-winclient-sdk/blob/master/Source/Facebook.Client/Session.cs#L513-L534

Note that Windows Phone login is implemented using Uri handling that contains a call to this event with a null pointer:

https://github.com/facebook-csharp-sdk/facebook-winclient-sdk/blob/master/Source/Facebook.Client/FacebookUriMapper.cs#L76

You can also fix this issue by making session change delegate public.