nginx refactoring

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.
nginx: looking for segfaults on the regression test.

If nginx segfaults it will return, warning that the test failed.
nginx: better dealing with chunked request body
nginx: copies 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:

 #15 - SecRequestBodyInMemoryLimit
 #16 - SecRequestBodyInMemoryLimit (greater)
 #19 - SecRequestBodyLimitAction ProcessPartial (multipart/greater - chunked)
 (from: regression/config/10-request-directives.t)
Regression: Accept different ports on FULL_REQUEST unit test.

FULL_REQUEST unit test was expecting only for the default regression test
suite port. Now it is expecting for [0-9]+.