add a Request::raw_post buffer

This buffer is used when a Function::NeedToCopyRawPost() method returned true.

while here:
- remove WINIX_POST_PARAMS and WINIX_RAW_POST_STRING plugin messages

winixd/core/request.h

@@ -180,6 +180,11 @@ public:
 	CookieTab   cookie_tab;
 	pt::Space	post_in;
 
+	/*
+	 * raw post input used if a Function::NeedToCopyRawPost() returned true
+	 */
+	pt::TextStream raw_post;
+
 	// input headers (without cookies)
 	// at the moment we are using FastCGI and HTTP headers are prefixed with 'HTTP_' string
 	// so we drop the prefix and change all characters to small ones