Nginx-related fixes

Refactoring on the nginx module, including:
 - Better handling larger posts;
 - Now using nginx echo module during the regression tests.
 - Better interacting with neginx chain rules
 - Separation of the request handling and content filters.
 - Better handling nginx sessions and resource counts to allow a
   more efficient garbage collector.
 - Handling both http/1.0 and 1.1, including keep-alive.
 - Tests are now capable to test nginx as a proxy or end-server.
 - Tested agains nginx 1.6 and 1.7.
 - better dealing with chunked request body
 - Refactoring: split lines longer than 80 characters, remove trailing whitespaces, change CRLF to LF
 - Copy the req body chain to be processed instead of move:

Add a check for the definition MOVE_REQUEST_CHAIN_TO_MODSEC, whenever it is
set the chain will be moved into the brigade. If it was not set the chain
will be only copied. Moving was causing segfaults on the following
regression tests:

 owasp-modsecurity#15 - SecRequestBodyInMemoryLimit
 owasp-modsecurity#16 - SecRequestBodyInMemoryLimit (greater)
 owasp-modsecurity#19 - SecRequestBodyLimitAction ProcessPartial (multipart/greater - chunked)
 (from: regression/config/10-request-directives.t)

Author: Felipe Zimmerle

nginx/modsecurity/apr_bucket_nginx.c

@@ -1,18 +1,24 @@
-#pragma once
-#include <ngx_core.h>
-#include "apr_buckets.h"
-
-apr_bucket * apr_bucket_nginx_create(ngx_buf_t *buf,
-                                     apr_pool_t *p,
-                                     apr_bucket_alloc_t *list);
-
-apr_bucket * apr_bucket_nginx_make(apr_bucket *e, ngx_buf_t *buf,
-                                   apr_pool_t *pool);
-
-#define ngx_buf_to_apr_bucket apr_bucket_nginx_create
-
-ngx_buf_t * apr_bucket_to_ngx_buf(apr_bucket *e, ngx_pool_t *pool);
-
-ngx_int_t move_chain_to_brigade(ngx_chain_t *chain, apr_bucket_brigade *bb, ngx_pool_t *pool, ngx_int_t last_buf);
-ngx_int_t move_brigade_to_chain(apr_bucket_brigade *bb, ngx_chain_t **chain, ngx_pool_t *pool);
-
+#pragma once
+#include <ngx_core.h>
+#include "apr_buckets.h"
+
+apr_bucket * apr_bucket_nginx_create(ngx_buf_t *buf,
+                                     apr_pool_t *p,
+                                     apr_bucket_alloc_t *list);
+
+apr_bucket * apr_bucket_nginx_make(apr_bucket *e, ngx_buf_t *buf,
+                                   apr_pool_t *pool);
+
+#define ngx_buf_to_apr_bucket apr_bucket_nginx_create
+
+ngx_buf_t * apr_bucket_to_ngx_buf(apr_bucket *e, ngx_pool_t *pool);
+
+ngx_int_t copy_chain_to_brigade(ngx_chain_t *chain_orig,
+		apr_bucket_brigade *bb, ngx_pool_t *pool, ngx_int_t last_buf);
+
+ngx_int_t move_chain_to_brigade(ngx_chain_t *chain, apr_bucket_brigade *bb,
+		ngx_pool_t *pool, ngx_int_t last_buf);
+
+ngx_int_t move_brigade_to_chain(apr_bucket_brigade *bb, ngx_chain_t **chain,
+		ngx_pool_t *pool);
+