working library

The library now works :) . But its not quite there yet, there are still some minor issues with the connections. 

Unavailable machines are automatically removed by calling a method validate_servers(), see connection.py. But this still takes too much time, around 5 seconds. 

I am also trying to restart the server when the client process dies unexpectedly. The current solution is not yet complete, it works in some cases and does not in others. I still have to investigate.