Asynchronous examples

I had some struggles using this lib with the intel galileo, the spi default options were not the same as the Rpi, so I made it accept the options as a parameter.

Also the examples code were tottaly synchronous and were blocking the nodeJS thread, so I turned them more async, got rid of the blocking lib sleep that doesn't work in windows.

I kept the forked code up to the main objective only and cleaned the socket.io part..

Feel free to merge if it helps the project