Issue-104

I am confused as to it's status. The issue is whether there is a  
disallowed vocabulary. The notes have Michael saying there is, and I  
an thinks there is. This would suggest that closing the issue means  
saying that there is a disallowed vocabulary and a pointer to the  
appropriate place in the spec. However, I don't understand Peter's  
comment suggesting a break in backwards compatibility in this light.

  I will review the current spec to find what Michael is referring  
to. However a summary of current understand so as to verify we're  
(including me) are all on the same page would help if someone happens  
to have the time to write.

-Alan