ResourceNamespace allows you to create nested resources, i.e. `stripe.issuing.cards`. It also works recursively, so you could do i.e. `stripe.billing.invoicing.pay`.
function ResourceNamespace(stripe, resources) {
  for (var name in resources) {
    var camelCaseName = name[0].toLowerCase() + name.substring(1);

    var resource = new resources[name](stripe);

    this[camelCaseName] = resource;
  }
}