HTTP/1.1: partial support for no-cache and private controls with parameters

HTTP/1.1: partial support for no-cache and private controls with parameters

Since we now support HTTP/1.1 storage and revalidation of
Cache-Control:no-cache it is important that we at least detect the cases
where no-cache= and private= contain parameters.

These are likely still rare occurances due to the historic lack of
support. So for now Squid just detects and exempts these responses from
the caching performed. The basic framework for adding handling of the
header lists is made available but not at this time used.