Fix decorating error with dependencies bound with FastBind()

[kekchpek]

FastBind() had used a casting to implementation class during adding dependency to ViewModels container. This casting was used in the provider-method, that had being added to ViewModels container to get the dependency from main container. It had raised an error on attempt to decorate any dependency, that is bound this way, because decorator is not an inheritor of decorated class. So the decorator could not be casted to original implementation class.

Now FastBind() do not use data about implementation this way and do not make any checks in ViewModels container provider-method.

Decorating example was added to demo project to keep autotests catch errors in this functionality.