[robocup-small] New Referee Box Protocol

[Michael Bleier]

Hi all,

One thing is bugging me for years. The keeper is only allowed to be 
exchanged in consensus with the referee. Unfortunately the referee has 
no way to signal this decision. Teams either can only change the keeper 
in a timeout or they rely on auto detection like using the robot in the 
defense area. I can come up with a couple scenarios when auto detection 
will fail and I have seen it happen during RoboCup.

Should we add a keeper exchange signal to the referee box or even send 
the active keeper id (this would also solve any arguing about which 
robot was the actual keeper)?

Cheers,
Michael