CI: Install libssl-dev & OCaml 'ssl' package
Include 'lwt.ssl' dependency

See: ARAKOON-428
See: http://jira.incubaid.com/browse/ARAKOON-428
Use 'Lwt_ssl' sockets

Not using any real SSL for now, just embedding plain sockets.

See: ARAKOON-428
See: http://jira.incubaid.com/browse/ARAKOON-428