[developers] MRS in PET SVN with selective packing

[Ann Copestake]

Benjamin.Waldron at cl.cam.ac.uk said:
> (ii) arrange  for these slots to be set appropriately when the MRS is
> constructed

but what's the understood semantics of the global cfrom/cto?  (I seem to 
remember it got put in at the request of Francis but I could well be wrong - 
however I am reasonably sure it wasn't my idea ...)  Another way of saying 
this - is there any situation when cfrom isn't min of the cfroms in the eps 
list and cto max of the ctos?  Is anybody relying on the global cfrom/cto, and 
if so, what do they take it to be?

Unless this has been documented somewhere, I think the questions should be put 
it to the rmrs list (suitably reformulated).  Ben - could you look after this, 
please?  I'm too short of time right now to follow this up.

Ann