Accept-encoding gzip etc.

Requesting a page from a site that automatically encodes page content using deflate or gzip will result in a failure to proxy the page successfully (its compressed, not raw text)
Sending the extra header stating you accept no encoding methods (empty string) will *request* that no compression is used in the response. 
see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
mh