Pass reused_session to connect()

[GuyLewin]

Version 1.6 introduced a unified httpc:connect() method for connecting to a server, and deprecated the old httpc:ssl_handshake() method.
We rely on reused_session (the first parameter of tcpsock:sslhandshake) to speed up our outgoing connections.
We'd love to have the option to set reused_session as part of the options table passed to httpc:connect().