Initializes the CKeyboardManager object.
If you call CWinAppEx::GetKeyboardManager, the default implementation of that method calls InitKeyboardManager.
If your application already has a keyboard manager and you call InitKeyboardManager, your application will have an ASSERT failure. Therefore, you should not call InitKeyboardManager if you create a CKeyboardManager object directly. If you are not using a custom CKeyboardManager, you should use GetKeyboardManager to create a CKeyboardManager object.