WebsocketServer: Initial import of Websocket support for JSON-RPC

Conventional JSPN-RPC implementations are based on HTTP connections. The
disadvantage of those implementations are that each request and response
is handled in a seperate TCP-socket. Websockets are only established
once. There is no need for establishing a new socket-connection for each
request. Every request gets handled via one connections (identified via
WebsocketProtocol)

Signed-off-by: Tom Doehring <toolmmy@googlemail.com>