Feature: Implement a handshake mechanism for the client-server communication

[JorchRL]

As I am running a local server to serve the assets, I don't want end users of the games made with this project to be able to mess with the server (that could be used for cheats or other malicious exploits).

And maybe give devs the option to change the "client" for the game. Either the native webkit window or a browser, or another alternative. As long as they can implement the handshake.

[JorchRL]

Closed in favor of implementing it in a separate library. See #29