The purpose of this module is to give you a fine-grained control over a URL's
query-string in Varnish Cache. It's possible to remove the query-string, clean
it, sort its parameters or filter it to only keep a subset of them.
This can greatly improve your hit ratio and efficiency with Varnish, because
by default two URLs with the same path but different query-strings are also
different. This is what the RFCs mandate but probably not what you usually
want for your web site or application.
A query-string is just a character string starting after a question mark in a
URL. But in a web context, it is usually a structured key/values store encoded
with the `application/x-www-form-urlencoded' media type. This module deals
with this kind of query-strings.
