Support for https

Hi,
my Odoo is behind an nginx proxy and served over https - the odoo node module only seem to support http.

Enabling https is trivial:
var http = require('http') -> var http = require('https')

and

var client = jayson.client.http(options); -> var client = jayson.client.https(options);

in lib/index.js but obviously this should be done through a configuration option.

Can this be included in the next version please?