Fix the need for rejectUnauthorized being false.

The tlsOptions object should include a host for certificate validation.

The documentation available at :http://nodejs.org/api/tls.html#tls_tls_connect_port_host_options_callback is a bit confusing but the tls.js file from Node.js clearly uses the hostname from the options object to do its certificate validation.

A workaround for the current version of the library would be to add, for example, host: 'imap.google.com' to the tlsOptions object.

This fix was tested with gmail. With this change, the error "Hostname/IP doesn't match certificate's altnames" disappears.