Upgrade nginx to 1.4.0 and remove devel (for now).

"nginx-1.4.0 stable version has been released, incorporating many new features developed in the 1.3.x branch - support for proxying of WebSocket connections, OCSP stapling, SPDY module, gunzip filter and more."

I removed the devel version for now, because according to [the download page](http://nginx.org/en/download.html), 1.4.0 is both the stable and devel version now.