Moving forward we're going to assume `mbstring.func_overload` is off.
For that reason we're not going to call `mb_` functions when checking byte level strings.
Separated handshake negotiation into its own class
`HandshakeNegotiator` deals with Request/Response classes
These changes are geared towards separate responsibility
Refs #29
Updated RFC6455 handshaker to check values case insensitively
Made sure RFC6455 handshaker matches encoding properly
Added mbstring as a requirement for Ratchet
Refs #28, #30
Updated how Ratchet handles WebSocket sub-protocols
Broke out WsServerInterface to not extend MessageInterface;
Components will instead use Interface segregation principle
WAMP is now able to work without the developer having to
manually enable the WAMP sub-protocol