PROTON-371: Created the Qpid::Proton::Terminus class.
PROTON-371: Created the Qpid::Proton::Endpoint class.

This is the base class for creating link, sender and receiver types.
PROTON-371: Created the Qpid::Proton::Link class.
PROTON-371: Created the Qpid::Proton::Sender class.
PROTON-371: Created the Qpid::Proton::Receiver class.