Prevent Nginx failing to daemonise by changing away from "NGINX"
environment variables for setting versions.  This *really* broke things.

This fixes #9 and #8 by reading headers_out from the subrequest resposne
and copying them into the main request's headers_out.  Previously, the
direct assignment (shallow copy) produced the effect whereby no filters
that ran after the shib module could modify headers.

The reason for this appears to be linking inside the ngx_list
``headers`` inside the request option; suffice to say, this is a much
better approach.

Turns out that subrequests aren't pushed through Nginx's header filters which means that a directive like add_header won't work in a shib_request (or auth_request etc).  Good to know!

This reverts commit f5bfd9ea.

This ensures that Nginx can still manipulate responses from
the Shibboleth authorizer.

fixed #6 by initialising hash member variable

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>