Add 'tunnelDomains' to options page

[brianjoyner]

Checked to see if the adding 'tunnelDomains' works within the sauceConnectLauncher options and it does.

Recommend updating readme to include this option.

var options = {
            username: username,
            accessKey: password,
            tunnelDomains : '*domain1.com,*domain2.net'
        };

        var promise = new Promise(function(resolve,reject){
            sauceConnectLauncher(options,function(error, sauceConnectProcess){
            if (sauceConnectProcess.tunnelId) {
                console.log('id = ' + sauceConnectProcess.tunnelId);
                resolve ();
            } else if (error){
                reject (error.message);                
            }
        });
        }).then(function(result){
            console.log('Tunnel Is Established');
        },function(error){
            console.log(error);
        });

        return promise;