Remove the shib_authorizer flag on the config, update readme

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>

This is to be used in conjunction with --add-module at nginx
configure time.

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>

This mostly follows the FastCGI Authorizer specification, with the
exception of the processing of the request and response bodies, and
variable naming.

See http://forum.nginx.org/read.php?2,238523,238523#msg-238523


for a lengthier discussion.

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>

Signed-off-by: Luca Bruno <luca.bruno@rocket-internet.de>