Add access class for ADL-free intrusive_ptr types
Add access class for ADL-free intrusive_ptr types

The new access trait provides an alternative to the ADL interface for
cases where adding the free functions is undesired. In particular when
interfacing CAF with another 3rd party library or C libraries (that
would otherwise require users to clutter the global namespace).

DavadDi/actor-framework,actor-framework/actor-framework,DavadDi/actor-framework,DavadDi/actor-framework,actor-framework/actor-framework,actor-framework/actor-framework,DavadDi/actor-framework,actor-framework/actor-framework