req.accepts_cache is incomplete about ledge

[pintsized]

14.9.4 Cache Revalidation and Reload Controls: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.4

[pintsized]

From the link above:

The request includes a "no-cache" cache-control directive or, for compatibility with HTTP/1.0 clients, "Pragma: no-cache". Field names MUST NOT be included with the no-cache directive in a request. The server MUST NOT use a cached copy when responding to such a request.

So the current test for Cache-Control: no-cache or Pragma: no-cache is actually correct (I'd assumed we should also be parsing fields). The piece we are missing is Cache-Control: max-age=NUM. I'll implement this now.