JavaScript: Add basic model of client-side socket.io API.

javascript/ql/test/library-tests/frameworks/SocketIO/client2.js

@@ -0,0 +1,16 @@
+var sock = require("socket.io-client")("ws://localhost");
+require("socket.io-client").connect("http://example.com/foo/bar?q=v#abc");
+
+sock.on('message', (x, y) => {
+  console.log(x, y);
+})
+
+sock.on(eventName(), (msg) => {});
+
+sock.on('data', (x, cb) => {
+  cb("received");
+});
+
+sock.emit('data', "hi", "there");
+
+sock.write("do you copy?", () => {});