[obs-tap] draft summary topic 3 : obs-title

[Mireille Louys]

Topic 3 : obs-title
We agreed it is an important data model field for the user to  
interpret what comes back from a query.
The free format helps humans to precisely describe a data set.  
Machines cannot search on this field because it not a standardised  
vocabulary.
The field name comes from the spectrumDM: DataID class and can be  
re-used with the same definition.
So I suggest we keep this field as optional in the ivoa.Obscore table.

Thanks for your comments.
--ML