Add support to generate REST resources that issue HTTP cache headers

This is more or less an issue that affects HTML5 scaffolding that depends on the generated REST resources.

Browsers like IE8/9/10 etc. aggressively cache responses unless instructed to not do so, ensuring that clients (like the scaffolded apps) do not issue additional requests beyond the first one, until the cache is cleared, or until the REST resources are modified.

We should therefore allow (possibly as an option) the generation of code within the REST resources that issue HTTP Cache-Control headers.