PushParser: fix PushParser.until not eating the marker

Change-Id: I4ea1ec38b665cf63ff71505558f77a2ef39dfaf7
SocketIO: Do not readd existing clients

Change-Id: I96ec2419f0711b58869f0146777ed314fa5c2c58
AsyncHttpServerResponse: fix bug where writeHead is called twice

Change-Id: I353bd5ae2c06664d1b7b2533626a7ffff6a5f5c9
WebSocket Server: Implement WebSocket server protocol option.

Change-Id: I02fc5e7ac4b0dbb688ad5789178f9e7643eea8a5