Use IPv6Endpoint instead of IPv6Address and port.
A Features instance is no longer associated with a Connection. Agent channel listeners are now responsible for responding to FeaturesRequest messages.
Remove features.h.
Add asio submodule, and use it instead of boost. Change all code to use asio::error_code.
More namespace clean up.
Add -fno-exceptions compiler flag.
Use variant of timer expires_from_now.
Capitalize Milliseconds.
Preliminary ssl support.  Tests pass.
Made sure that code still runs using PlaintextSocket. Added configureTLS method to Driver.
Remove Exception class. Use std::error_code.
Minor cleanup.
TCP_Connection is now a template that parameterizes on a PlaintextSocket or an
EncryptedSocket.