[osis-core] Is this ready for OSIS 1.1? Overlapping heirarchies

[Harry Plantinga]

> >There seems to be little help for multiple overlapping heirarchies.
> >
> If you check the message that arrived while you were dodging forest 
> fires you will find messages essentially concedeing  that we don't have 
> a good solution for overlap but that we will address that issue again in 
> OSIS 2.0.

We essentially decided to give the <seg> approach (split container elements
that are linked together) a try in OSIS 1.1, to see if it's workable. We'll
revisit the problem with OSIS2.0.  This is one of the major areas of
Steve's research, if I remember prior messages correctly.

One ad-hoc way of reducing overlap problems that was suggested 
(not decided upon as far as I know) was to have a milestone-like 
option for the <q> element, e.g. 

<q mStart="id1" /> ... <q mEnd="ID1" />

Then event-oriented software could still treat the quote as a container,
while the majority of the problems with multiple-hierarchy-overlap 
thus far identified would be elimintated.

-Harry