Support rack-wwwhisper and connect-wwwhisper middlewares

[wrr]

Current scripts and documentation allow to setup wwwhisper with nginx. We have middlewares to easily integrate wwwhisper with Ruby's Rack and Node.js's Connect, but currently the middlewares are used only with wwwhisper service on Heroku.

The documentation and setup scripts need to be extended to allow using the middlewares with standalone wwwhisper instances. For example, current setup uses Unix socket for communication between nginx and wwwhisper. For Rack and Connect, standard TCP port is needed.