Make tokens globally unique across the whole application.

This branch makes tokens unique across the whole application. That means that participants cannot have the same tokens as anonymous participants, for example. It is also not possible to set the token to the organizer token at any time, or to have the organizer token accidentially the same as a participant or audience token.

It also changes the checkstyle as side effect to allow for the while of do-while to be on the same line as the right curly.