Merge SocketClient component into this component

[clue]

Here's the current situation:

• This Socket component: Async, streaming plaintext TCP/IP and secure TLS socket server for ReactPHP
• SocketClient component: Async, streaming plaintext TCP/IP and secure TLS socket client for ReactPHP

This is not exactly ideal, they share quite a bit of common code and actually have a dependency on one-another for their test suite.

Also, I believe this situation may be a bit confusing for consumers of this package. In particular our Datagram component provides both client and server side for datagram sockets (UDP).

As such, I'd vote for merging these two components into a single Socket component.

[clue]

Deferred to future release as per #75. I'm working on getting this resolved this week