for those who are interested

 xo-pfloat now compiles with somewhat horrible output  
          (but never finishes the last page)

 xo-balance compiles and finishes

basically the whole module is broken since I started to add balancing support,
way back (and then got sidetrack with a couple of books).

however, it is now using all the new kernel commands so it doesn't fall over
with unknown syntax, which is a start.

 - if you want to try, you basically need all of the xor module anew (and
   probably some of the expl3 core as well, as i had to fix one or the other
   thing there too.

frank