Squid Proxy Configuration

Turning this on provides a partial fix to the problem, by causing all IMS-REFRESH requests from older IE versions to check the origin server for fresh content.  This reduces hit ratio by some amount (~10% in my experience), but allows users to actually get fresh content when they want it.  Note that because Squid cannot tell if the user is using 5.5 or 5.5SP1, the behavior of 5.5 is unchanged from old versions of Squid (i.e. a forced refresh is impossible).  Newer versions of IE will, hopefully, continue to have the new behavior and will be handled based on that assumption.  This option defaults to the old Squid behavior, which is better for hit ratios but worse for clients using IE, if they need to be able to force fresh content.