clients should assume http protocol

[DonutEspresso]

When creating a new http client (JSON or otherwise), if the passed in host name doesn't have a http protocol you'll get an ECONNREFUSED error after about 5-10 seconds:

var client = restify.createJsonClient({
    url: 'www.google.com'
});

client.get('/', function() {...});

Should Restify assume http by default?