FIX: on HHVM, stream_socket_client returns $errno of NULL on success.
FIX: stream_socket_client can return FALSE which indicates an error (see php.net/stream_socket_client).
Merge pull request #110 from rp-eric/master

stream_socket_client may return FALSE (and $errno may be NULL on HHVM)
Bump version to 1.17.3
Update tests to latest version