ser2nets (multi-conns & multi-ports)

Enable multiple connections for ser2net 2.7.
Port can also be bound to multiple devices.

ser2net with new 'rraw' and 'http' (websocket) state

Enhanced ser2net with two new states:
rraw: enable ser2net to connect to a remote port, e.g. 127.0.0.1,8081:rraw:3:/dev/ttyS0:38400
http: enable HTTP/WebSocket connections