Add support for the secureProtocol TLS option.

Adding support for the `secureProtocol` TLS option. This allows one to set the SSL method to use. Without this, if one tries to make a connection using secure WebSockets to a server that only supports SSLv3, the connection will fail with an error message similar to:

    Connect Error: { [Error: socket hang up] code: 'ECONNRESET', sslError: undefined }

This is because by default, Node.js does not enable support for SSLv3 in the TLS options.

**Aside:** I wonder if a better way of allows users to pass through options is to just copy all of the keys from the `config.tlsOptions` object and let Node.js figure out what key are valid/invalid.