The webserver example found in the master branch is working. Simply compile the project and upload the program to your EV3. When the webserver has started (which takes a while) simply type in http://yourIp:yourPort/documentation to see a list of what is currently supported. Please note that using port 80 is not working so use something like 8080. As you will see from the URL list the webserver is written as a REST service so data is retrieved via JSON – so writing a client that that can interact/control the EV3 is fairly simple.