Added sunxi_server to allow a client running without privileged user acc...

I needed to controll the LED from the WebServer and dont like to run to many processes with privilges - therefore I added sunxi_server/drb_pin.rb.

I have tested it, and it is working nicely, however a good code-review and some additional checks wont harm.

README.md is updated with an example.

I am using Ruby.DRB for different purposes now.