Creates the test for the SocketIO extension and adds it to the boot files

[socketio-jsb] add SocketIO JS extension test, update test menu and boot files
[socketio-jsb] add socket.io client library to external sources
[socketio-jsb] modify test to include getTag and setTag handlers
[socketio-jsb] correct on handler declarations and streamline client tagging with a map of names and sockets
[socketio-jsb] correct on handler declarations and streamline client tagging with a map of names and sockets
[socketio-jsb] further streamline jsb vs js codes
[socketio-jsb] remove sockets[] register in favor of tag property
[socketio-jsb] correct identifier