Changed the way Radios get added to clients and servers.

The server now sends all radios and their playlits on clientendpoint
initialization and diffs from there on after. This way the model gets reset
less often.
Some cleanup of the connection class
Restored the gracefull server shutdown.
Server now continues to run as normal when a client unexpectedly closes
Moved connection to the gui instead of command line arguments.
Improved client robustness, now keeps running when server unexpected disconnects
Moves all gui sources to the gui folder.