Bacon should send sane caching headers

[igalic]

Right now, bacon starts a PHP session at the, which causes it to send response headers such as these:

HTTP/1.1 200 OK
Host: localhost:8080
Connection: close
X-Powered-By: PHP/5.4.9-4ubuntu2
Set-Cookie: 5fff0c76cab5500d8ff289d2d37de289d3214d0f=ah0dds0f6003u7cgt3jel18qpjo6ic9a; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Set-Cookie: 5fff0c76cab5500d8ff289d2d37de289d3214d0f=44nt3jt9dmp4obe4b7b1laefjhgml9mk; path=/
Content-type: text/html

While this is a good default for a highly dynamic site with heavy user-interaction, it's not a very good default for… everything else.

The reason for these headers is PHP's defaults for session_cache_limiter and session_cache_expire.
Perhaps we should make those configurable (on a per-route basis?)