Look into HTTPS support

[clue]

HTTPS is supported right now…kind of…

This should work reasonably well in recent PHP versions. Several changes to the underlying react/socket-client component and PHP itself contribute to quite a different behavior.

For example, accessing https://svn.apache.org does not work in PHP 5.3, because it does not use the correct SNI headers.

At the very least, this needs some documentation to raise awareness.

[clue]

Also, HHVM doesn't support SSL/TLS connections at all: reactphp-legacy/socket-client#27

[clue]

See PR #51, this change depends on the newest SocketClient release which in turn requires reactphp/http-client#55 (merged) and reactphp/http-client#56 (pending).