Specify the location of the executable for the Store URL rewriter.
	The Store URL rewriter allows URLs to be "normalised" ; mapping
	multiple URLs to a single URL representation for cache operations.

	For example, if you request an object at:

	http://srv1.example.com/image.gif

	and a subsequent request for:

	http://srv2.example.com/image.gif

	then Squid will treat these both as different URLs and cache them
	seperately.

	This is almost the normal case, but an increasing number of sites
	distribute the same content between multiple frontend hosts.
	The Store URL rewriter allows you to rewrite these URLs to one URL
	to use for cache operations, but not -fetches-. Fetches are still
	made from the original site, but stored with the store URL rewritten
	URL as the store key.

	For each requested URL rewriter will receive on line with the format

	URL <SP> client_ip "/" fqdn <SP> user <SP> method <SP> urlgroup
	 [<SP> kvpairs] <NL>

	In the future, the rewriter interface will be extended with
	key=value pairs ("kvpairs" shown above).  Rewriter programs
	should be prepared to receive and possibly ignore additional
	whitespace-separated tokens on each input line.

	And the rewriter may return a rewritten URL. The other components of
	the request line does not need to be returned (ignored if they are).

	By default, a Store URL rewriter is not used.

	Please note - the normal URL rewriter rewrites Squid's _destination_
	URL - ie, what it fetches. The Store URL rewriter rewrites Squid's
	_store_ URL - ie, what it uses to store and retrieve objects.