TUIO: implement the 2.0 specification

http://tuio.org/?tuio20

It's quite different from the 1.x specs. But it supports fiducial markers with non-trivial IDs such as UUIDs. That should be put into the uniqueId for each touchpoint (or into the "tool" object), added here: https://codereview.qt-project.org/#/c/152292/