Add uwsgi support

[mvintila]

Add uwsgi support, very similar to fastcgi. Actually most of the code is just copied over from the fastcgi functionality. This is tested and currently running in a production environment.

[mvintila]

Tests are fixed, would be nice if this was merged eventually.

[jfryman]

@mvintila thanks for the code.

Yeah, I'm good with this. I know it can be done with custom directives, but this is cool to merge.

[3flex]

Why doesn't uwsgi_params match upstream? What was committed contains this extra line:

uwsgi_param SERVER_ADDR $server_addr;

[mvintila]

What do you mean? The file is identical to the example here:
http://uwsgi-docs.readthedocs.org/en/latest/Nginx.html

[3flex]

This is the current file in nginx source: http://trac.nginx.org/nginx/browser/nginx/conf/uwsgi_params

You wouldn't include uwsgi_param HTTPS $https if_not_empty; from upstream because that's only supported in nginx 1.1.1 and higher, but otherwise I'd expect the file in this module to match upstream.

[3flex]

@jfryman what do you want to do here? I'm trying to avoid a repeat of #500