PC connectivity

[mid-kid]

Allow the arduino implementation to communicate with a PC to support actually establishing a connection on-line.
This requires a PC client application to relay information and configure the program, and should be usable by other implementations on other microcontrollers.

[arves100]

partially implemented in d7be2586836a126cfc23403c8c8e508207720294 + https://github.com/REONTeam/PCBridge

Issue left:
Handling of 254 bytes of data with a sane serial speed
tcp listen+accept