Add http status code to render method

It would be nice if we could do something like:

render(template: "/common/errors", model: [bean: iterationType], status: 500)

Instead of:

response.setStatus(500)
render(template: "/common/errors", model: [bean: iterationType])

For sending HTTP status to the browser. It's nice for doing AJAX where there is an error callback in the JS code.